Question

Solve for x.

5x2 – 80 = 0

A.
{16, –16}

B.
{16}

C.
{4}

D.
{4, –4}

Answer 1

Answer is D. 5x2 - 80 = 0 5x2 = 0+80 5x2 = 80 x2 = 80/5 x2 = 16 By taking sqr root of both sides, we get x = 4 and x = -4 So, the answer is {4, –4}

Answer 2

x = {-4, 4}

Divide each side by '5'. x2 = 16 Simplifying x2 = 16 Take the square root of each side: x = {-4, 4}