How do you solve |-4x + 5| + 3 = 30?

1 Answer
Oct 16, 2017

See a solution process below:

Explanation:

First, subtract color(red)(3) from each side of the equation to isolate the absolute value function while keeping the equation balanced:

abs(-4x + 5) + 3 - color(red)(3) = 30 - color(red)(3)

abs(-4x + 5) + 0 = 27

abs(-4x + 5) = 27

The absolute value function takes any term and transforms it to its non-negative form. Therefore, we must solve the term within the absolute value function for both its negative and positive equivalent.

Solution 1:

-4x + 5 = -27

-4x + 5 - color(red)(5) = -27 - color(red)(5)

-4x + 0 = -32

-4x = -32

(-4x)/color(red)(-4) = (-32)/color(red)(-4)

(color(red)(cancel(color(black)(-4)))x)/cancel(color(red)(-4)) = 8

x = 8

Solution 2:

-4x + 5 = 27

-4x + 5 - color(red)(5) = 27 - color(red)(5)

-4x + 0 = 22

-4x = 22

(-4x)/color(red)(-4) = (22)/color(red)(-4)

(color(red)(cancel(color(black)(-4)))x)/cancel(color(red)(-4)) = -22/4

x = -11/2

The Solutions Are: x = 8 and x = -11/2