Question

What is the solution set for the quadratic equation x2 - 16 = 0?

A)
{4}


B)
{-4, 4}


C)
{256}


D)
{-256, 256}

Answer 1

B) {-4, 4}

Proof:

Solve for x over the real numbers:
x^2 - 16 = 0

The left hand side factors into a product with two terms:
(x - 4) (x + 4) = 0

Split into two equations:
x - 4 = 0 or x + 4 = 0

Add 4 to both sides:
x = 4 or x + 4 = 0

Subtract 4 from both sides:

Answer: x = 4 or x = -4