Answer:
x = -3, 4/5
Explanation:
To factor the equation, you need to find factors of (5)(-12) that have a sum of (+9).
(5)(-12) = -60 = 60(-1) = 30(-2) = 15(-4) = 12(-5) = 10(-6)
The factors 15 and -4 have a sum of 9, so we can factor the equation as ...
5x² +15x -4x -12 = 0
5x(x +3) -4(x +3) = 0 . . . . factor pairs of terms
(5x -4)(x +3) = 0
The solutions are the values of x that make these factors zero:
5x -4 = 0 ⇒ x = 4/5
x +3 = 0 ⇒ x = -3
The solutions are x = -3 or 4/5.