MA.912.AR.1.2

Rearrange equations or formulas to isolate a quantity of interest.

Examples

Algebra 1 Example: The Ideal Gas Law PV = nRT can be rearranged as begin mathsize 12px style T equals fraction numerator P V over denominator n R end fraction end style to isolate temperature as the quantity of interest. 

Example: Given the Compound Interest formula begin mathsize 12px style A space equals space P left parenthesis 1 plus r over n right parenthesis to the power of n t end exponent end style, solve for P

Mathematics for Data and Financial Literacy Honors Example: Given the Compound Interest formula begin mathsize 12px style A space equals P left parenthesis 1 plus r over n right parenthesis to the power of n t end exponent end style, solve for t.

Clarifications

Clarification 1: Instruction includes using formulas for temperature, perimeter, area and volume; using equations for linear (standard, slope-intercept and point-slope forms) and quadratic (standard, factored and vertex forms) functions. 

Clarification 2: Within the Mathematics for Data and Financial Literacy course, problem types focus on money and business.

Alternate version of this benchmark for students with significant cognitive disabilities.

Connecting Benchmarks/Horizontal Alignment

 

Terms from the K-12 Glossary

  • Equation

 

Vertical Alignment

Previous Benchmarks

Next Benchmarks

 

Purpose and Instructional Strategies

In grade 8, students isolated variables in one-variable linear equations and one-variable quadratic equations in the form x= p and  x= q. In Algebra I, students isolate a variable or quantity of interest in equations and formulas. Equations and variables will focus on linear, absolute value and quadratic in Algebra I. In later courses, students will highlight a variable or quantity of interest for other types of equations and formulas, including exponential, logarithmic and trigonometric.
  • Instruction includes making connections to inverse arithmetic operations (refer to Appendix D) and solving one-variable equations. 
  • Instruction includes justifying each step while rearranging an equation or formula. 
    • For example, when rearranging A = P(1 + rn)nt   for P, it may be helpful for students to highlight the quantity of interest with a highlighter, so students remain focused on that quantity for isolation purposes. It may also be helpful for students to identify factors, or other parts of the equations.

 

Common Misconceptions or Errors

  • Students may not have mastered the inverse arithmetic operations. 
  • Students may be frustrated because they are not arriving at a numerical value as their solution. Remind students that they are rearranging variables that can be later evaluated to a numerical value. 
  • Having multiple variables and no values may confuse students and make it difficult for them to see the connections between rearranging a formula and solving a one-variable equation.

 

Strategies to Support Tiered Instruction

  • Instruction includes doing a side-by-side comparison of solving a multistep equation with rearranging equations and formulas. The teacher should allow students time to understand that the steps in solving both equations are the same. 
    • For example, solve both equations and note the similarities in solving both types of equations. 
      Table
  • Teacher provides a chart for students to use as a study guide or to copy in their interactive notebook. 
    • For example, inverse operations chart below.
      Table

 

Instructional Tasks

Instructional Task 1 (MTR.4.1, MTR.5.1
  • Part A. Given the equation ax2 + bx + c = 0, solve for x
  • Part B. Share your strategy with a partner. What do you notice about the new equation(s)?

Instructional Task 2 (MTR.4.1MTR.5.1
  • Part A. Given the equation Ax + By = C, solve for B
  • Part B. Given the equation 7x − 6y = 24, determine the x- and y-intercepts. 
  • Part C. What do you notice between Part A and Part B?

 

Instructional Items

Instructional Item 1 
  • Solve for x in the equation 3x + y = 5xxy

Instructional Item 2 
  • The formula dExpression relating to the translational of motion, where d represents distance, v0 represents initial velocity, vt represents final velocity, and t represents time. Rearrange the formula to isolate final velocity. 

Instructional Item 3 
  • The area A of a sector of a circle with radius r and angle-measure S (in degrees) is given by Expression solve for the radius r.

 

 

*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.

General Information

Subject Area: Mathematics (B.E.S.T.)

Grade: 912

Strand: Algebraic Reasoning

Standard: Interpret and rewrite algebraic expressions and equations in equivalent forms.

Date Adopted or Revised: 08/20

Status: State Board Approved

This benchmark is part of these courses.