Using quadratic formula calculate x^2-2x-15

Answer 1

To use the quadratic formula, let's first identify the coefficients a, b, and c in the quadratic equation: x^2 - 2x - 15 = 0.

In this case:
a = 1 (coefficient of x^2)
b = -2 (coefficient of x)
c = -15

Now, substitute these values into the quadratic formula: x = (-b ± √(b^2-4ac)) / (2a)

x = (-( -2) ± √((-2)^2 - 4(1)(-15))) / (2(1))

x = (2 ± √(4 + 60)) / 2

x = (2 ± √64) / 2

x = (2 ± 8) / 2

Option 1: x = (2 + 8) / 2 = 10 / 2 = 5
Option 2: x = (2 - 8) / 2 = -6 / 2 = -3

Hence, the solutions to x^2 - 2x - 15 = 0 are x = 5 and x = -3.