Question

Find the sum of all solutions to the equation $3x(x+4) = 135$.

Answer 1

Answer:

-4

Step-by-step explanation:

3x(x + 4) = 135

3x² + 12x = 135

3x² + 12x - 135 = 0

On dividing by 3

x² + 4x - 45 = 0

x² + (9x - 5x) - 45 = 0

x² + 9x - 5x - 45 = 0

x(x + 9) - 5(x + 9) = 0

(x + 9)(x - 5) = 0

x = 5 & -9

Sum = -9 + 5

Sum = -4