x^2+2x-15=0

Question

i do not understand how to solve this equation all it says is to Solve each Quadratic Equation.

Answer 1

x² + 2x -15 = 0

Separate variables and constants aside by adding 15 to each side.

x² + 2x = 15

 To change the expression into a perfect square trinomial add (half the x coefficient)² to each side of the expression

 Here x coefficient = 2. so, (half the x coefficient)² = (2/2)²= 1

Add 1 to each side

x² + 2x + 1 = 15 + 1

(x + 1)²= 16

Take square root both sides

x + 1 = ±√16

x = -1 ± 4

x = 3, -5