EXAMPLE 9 Solve A =
Strategy To solve for b, we will treat b as the only variable in the equation and use
properties of equality to isolate it on one side. We will treat the other variables as if
they were numbers (constants).
Why
To solve for a specified variable means to isolate it on one side of the equation.
We use the same steps to solve an equation for a specified variable that we use to solve equations with only one variable.

We must isolate b on one side of the equation.
A =
bh
Solution
=bh for b.
24
2-A = 2.
21
a=
= bh
b
||
=
2-10
=
=
24
h
h
Self Check 9 Solve the following for a.
A = r²¹a
I
To clear the equation of the fraction, multiply both sides by 2.
Simplify.
To isolate b, undo the multiplication by h by dividing both sides by h.
On the right side, remove the common factor of h: bh/h = b.
Reverse the sides of the equation so that b is on the left.