Download Literal Equations

Rewrite Equations and
Formulas
Lesson 3.8
OBJ: To recognize and solve literal
equations; to rewrite equations and
formulas.
Literal Equation

An equation with two or more variables.
 An equation in which letters are used to
replace coefficients and constants of
another equation.
 Examples:
2
A  r
x1 x2  3  0
ax  b  c
P  2l  2 w
Solving Literal Equations
Solving equations for one variable in
terms of the other variables without
substituting any values.
 Examples:

Solve V =lwh for h.
 Solve A = p +prt for r.
 Solve A = p + prt for p.

**Use the same rules for solving equations. The only
difference is that it is not numbers, it is only variables.
Solve literal equations
Solve ax + b = c for x. Then use the
solution to solve 2x + 5 = 11
 Step 1: Solve ax + b = c for x
 Step 2: Use the solution to solve
2x + 5 = 11.
 The solution of 2x + 5 = 11 is 3.
 Example: Solve p + qx = r for x. Then
use the solution to solve 3+5x = -7.

Two or more variables…
Write -2x + 3y = 6 so that y is a function
of x.
 This means solve for y.
 Write 12 = 9x + 3y so that y is a function
of x.
 Write 14 = 7y – 6x so that y is a function
of x.

Solve and use Geometric Formulas
The area for a rectangle is given by the
formulas A = lw, where l is the length and
w is the width.
 Solve the formula for the length l.
 Use the rewritten formula to find the
length of this rectangle.

A = 351 cm2
13 cm
Homework

Text p. 187- 188

#’s 3-6, 12 – 18 evens, 20 -22, 24, 26, 27,
32, 33