Question

URGENT.

Solve for x.
x^2 − 16 = 9
||||| A) x = 3 or −3
||||| B) x = 4 or −4
||||| C) x = 5 or −5
||||| D) x = 6 or −6

Answer 1

C

Explanation:

First, begin by adding 16 to the other side of the equation.

x^2-16=9

x^2=25

Then, take the square root of both sides, which will cancel the "squared" on the x.

x=±5

It is plus or minus, because

5*5=25

and

-5* -5=25

Answer 2

C) x = 5 or −5

Explanation:

x^2 − 16 = 9

Add 16 to each side

x^2 − 16+16 = 9+16

x^2 = 25

Take the square root of each side

sqrt(x^2) = sqrt(25)

x = ±5