Page 186 - Algebra 1

L E S S O N Solving Literal Equations 29
Warm Up
New Concepts
1. Vocabulary A (constant, variable) is a letter used to represent
(2)
an unknown.
2. Evaluate the expression rt if r = 4 and t = 7.
(9)
3. Solve the equation 3x - 24 = 6. (26)
4. Solve the equation 4x + 14 = 2x + 20. (28)
5. Solve the equation 5x + 2 = 2x - 9. (28)
Recall when solving an equation with one variable, inverse operations are used to isolate the variable as shown below.
2x - 6 = 14 +__6 = +__6
Add 6 to undo subtracting 6. Simplify.
Divide by 2 to undo multiplication. Simplify.
2x = 20 2x = 20
__ 22
x = 10
A literal equation is an equation with more than one variable. As in an equation with one variable, use inverse operations and properties of equalities to solve for a specific variable in a literal equation. The solution for the specific variable will be in the terms of the other variables and numbers.
Solving for a Variable
Solve for y: 2x + 3y = 10. Justify each step. SOLUTION
Math Reasoning
Connect Give an example of an equation that would contain more than one variable.
Example
1
2x + 3y = 10
Find y in the equation.
Subtract 2x to eliminate from the y side. Simplify.
Divide by 3 to eliminate the coefficient of y.
Simplify.
If the variable being solved for is on both sides of the equation, the first step is to eliminate the variable on one side or the other.
-_ 2 _ x
= -_ 2 _ x 3y= -2x+10
3y= -2x+10 ___
333 __
y = -2x + 10 33
Online Connection www.SaxonMathResources.com
Lesson 29 171