How do you simplify (x^2 + x-12 )/( 2x^2 - 3x - 9?

1 Answer
Jun 14, 2018

See a solution process below:

Explanation:

First, factor the numerator and denominator of the expression as:

((x -3)(x + 4))/((2x + 3 )(x - 3))

Next, cancel the common terms from the numerator and denominator:

(color(red)(cancel(color(black)((x -3))))(x + 4))/((2x + 3 )color(red)(cancel(color(black)((x -3))))) =>

(x + 4)/(2x + 3)

However, because we cannot divide by 0 we must ensure:

2x + 3 != 0 and x - 3 != 0

Or

Condition 1:

2x + 3 != 0

2x + 3 - color(red)(3) != 0 - color(red)(3)

2x + 0 != -3

2x != -3

(2x)/color(red)(2) != -3/color(red)(2)

(color(red)(cancel(color(black)(2)))x)/cancel(color(red)(2)) != -3/2

x != -3/2

Condition 2:

x - 3 != 0

x - 3 + color(red)(3) != 0 + color(red)(3)

x - 0 != 3

x != 3

Therefore, the simplified expression is:

(x + 4)/(2x + 3) Where x != -3/2 and x != 3