Question

What are the roots of the equation x^2+4x-16=0

Answer 1

x² + 4x - 16 = 0
x = -(4) ± √((4)² - 4(1)(-16))
2(1)
x = -4 ± √(16 + 64)
2
x = -4 ± √(80)
2
x = -4 ± 4√(5)
2
x = -2 ± 2√(5)
x = -2 + 2√(5) U x = -2 - 2√(5)

Answer 2

OK so you need to use the quadratic formula with a=1, b=4, c=-16.

−b±√b^2−4ac
x= ------------------
2a

−(4)±√(4)^2−4(1)(−16)
x= -----------------------------
2(1)

−4±√80
x= ---------------
2

Your final answer is: x=−2+2√5 or x=−2−2√5