## Accelerated GSE Algebra I/Geometry A: Unit Descriptions

The fundamental purpose of Accelerated Algebra I/Geometry A is to formalize and extend the mathematics that students learned in the middle grades. The critical areas, organized into units, deepen and extend understanding of functions by comparing and contrasting linear, quadratic, and exponential phenomena. The Mathematical Practice Standards apply throughout each course and, together with the content standards, prescribe that students experience mathematics as a coherent, useful, and logical subject that makes use of their ability to make sense of problem situations. The pacing suggested below will allow students to gain a foundation in linear, quadratic, and exponential functions before they are brought together to be compared/contrasted in Unit 5. Although units 2, 3, and 4 look lengthy in terms of the number of standards, only their application to one function type per unit will be addressed. As key characteristics of functions are introduced in unit 2 and revisited within units 3, 4, and 5, students will gain a deeper understanding of such concepts as domain and range, intercepts, increasing/decreasing, relative maximum/minimum, symmetry, end behavior, and the effect of function parameters. Unit 5 will also provide an excellent opportunity for review of many concepts in preparation for the administration of the Georgia Milestones EOC assessment. Unit 7 begins the study of geometry concepts by building upon work students have done in 8^{th} grade. Unit 8 continues to build upon previous learnings to build a formal understanding of similarity and congruence. The last unit of the course builds upon similarity and the Pythagorean Theorem in the study of right triangle trigonometry.

Unit 1: By the end of eighth grade students have had a variety of experiences working with expressions. In this unit, students solve problems related to unit analysis and interpret the structure of expressions. This unit develops the structural similarities between the system of polynomials and the system of integers. Students draw on analogies between polynomial arithmetic and base-ten computation, focusing on properties of operations, particularly the distributive property. Students connect multiplication of polynomials with multiplication of multi-digit integers. In this unit, students also use and explain properties of rational and irrational numbers and rewrite (simplify) radical expressions. The current unit expands students’ prior knowledge of radicals, differences between rational and irrational numbers, and rational approximations of irrational numbers. The properties of rational and irrational numbers and operations with polynomials have been included as a preparation for working with quadratic functions later in the course. This content will provide a solid foundation for all subsequent units.

Unit 2: By the end of eighth grade students have had a variety of experiences creating equations. In this unit, students continue this work by creating equations to describe situations. By the end of eighth grade, students have learned to solve linear equations in one variable and have applied graphical and algebraic methods to analyze and solve systems of linear equations in two variables. This unit builds on these earlier experiences by asking students to rearrange formulas to highlight a quantity of interest, analyze and explain the process of solving an equation, and to justify the process used in solving a system of equations. Students develop fluency writing, interpreting, and translating between various forms of linear equations and inequalities, and using them to solve problems. Students explore systems of equations, find, and interpret their solutions. Students create and interpret systems of inequalities where applicable. For example, students create a system to define the domain of a particular situation, such as a situation limited to the first quadrant. The focus is not on solving systems of inequalities. Solving systems of inequalities can be addressed in extension tasks. All this work is grounded on understanding quantities and on relationships between them. In earlier grades, students define, evaluate, and compare functions and use them to model relationships between quantities. In this unit, students expand their prior knowledge of functions, learn function notation, develop the concepts of domain and range, analyze linear functions using different representations, and understand the limitations of various representations Students investigate key features of linear graphs and recognize arithmetic sequences as linear functions. Some standards are repeated in units 3, 4, and 5 as they apply to quadratics and exponentials.

Unit 3: In earlier grades, students define, evaluate, and compare functions, and use them to model relationships between quantities. In this unit, students strengthen their understanding of function notation and domain and range. Students interpret functions given graphically, numerically, symbolically, and verbally, translate between representations, and understand the limitations of various representations. They work with functions given by graphs and tables, keeping in mind that, depending upon the context, these representations are likely to be approximate and incomplete. When functions describe relationships between quantities arising from a context, students reason with the units in which those quantities are measured. In this unit, students analyze only quadratic functions and their characteristics. Students learn to anticipate the graph of a quadratic function by interpreting various forms of quadratic expressions. In particular, they identify the real solutions of a quadratic equation as the zeros of a related quadratic function. Students investigate key features of graphs, solve quadratic equations by taking square roots, factoring (*x*^{2} + *bx* + *c* AND *ax*^{2} + *bx* + *c*), completing the square, and using the quadratic formula. Students compare and contrast graphs in standard, vertex, and intercept forms. Students only work with real number solutions.

Unit 4: In this unit, students analyze exponential functions only. Students build on and informally extend their understanding of integer exponents to consider exponential functions. Students apply related linear equations solution techniques and the laws of exponents to the creation and solution of simple exponential equations. Students create, solve, and model graphically exponential equations. Students investigate a multiplicative change in exponential functions. Students interpret geometric sequences as exponential functions. Students reinforce their previous understanding of characteristics of graphs as they investigate key features of exponential graphs.

Unit 5: In this unit, students deepen their understanding of linear, quadratic, and exponential functions as they compare and contrast the three types of functions. Students distinguish between additive and multiplicative change and interpret arithmetic sequences as linear functions and geometric sequences as exponential functions. Students compare characteristics of linear, quadratic, and exponential functions. Students observe using graphs and tables that a quantity increasing exponentially eventually exceeds a quantity increasing linearly, quadratically, or (more generally) as a polynomial function. Students select from among these functions to model phenomena.

Unit 6: This unit builds upon students’ prior experiences with data, providing students with more formal means of assessing how a model fits data. Students use regression techniques to describe approximately linear relationships between quantities. They use graphical representations and knowledge of the context to make judgments about the appropriateness of linear models. Students interpret slope and the intercept of a linear model in context. Students compute (using technology) and interpret the correlation coefficient of a linear fit. Students also distinguish between correlation and causation. Students use measures of center (median, mean) and spread (interquartile range, mean absolute deviation) to compare two or more different data sets. Students interpret differences in shape, center, and spread of the data sets in context. In this unit, students decide if linear, quadratic, or exponential models are most appropriate to represent the data.

Unit 7: In previous grades, students have experience with rigid motions: translations, reflections, and rotations. Work in this area continues to build upon those experiences and makes the connections to transformations of geometric figures.

Unit 8: Students apply their earlier experience with transformations and proportional reasoning to build a formal understanding of similarity and congruence. They identify criteria for similarity and congruence of triangles and use them to solve problems. It is in this unit that students develop facility with geometric proof. They use what they know about congruence and similarity to prove theorems involving lines, angles, triangles, and other polygons. They explore a variety of formats for writing proofs.

Unit 9: Students apply similarity in right triangles to understand right triangle trigonometry, with particular attention to special right triangles and the Pythagorean Theorem.

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