Question

What is the value of x, when x2 + 5 = 21?

Answer 1

2x+5=21
-5 -5
2x=16
Divide both sides by 2
x=8

Answer 2

Think she meant x^2 right?

Answer 3

yeah

Answer 4

x^2 + 5 = 21


x^2 = 21 - 5


x^2 = 16


x = sqrt(16) or x = -sqrt(16)


x = 4 or x = -4

Answer 5

Don't forget about the plus minus since (-4)^2 = 16 as well as (4)^2 = 16