Question

solve $y = x^2 - 18$ for $x$.
a. $x = y + 18$
b. $x = \pm\sqrt{y + 18}$
c. $x = y - 18$
d. $x = \pm\sqrt{y - 18}$

Explanation:

Step1: Isolate the $x^2$ term

Add 18 to both sides:
$y + 18 = x^2$

Step2: Solve for $x$

Take square root of both sides:
$x = \pm\sqrt{y + 18}$

Answer:

B. $x = \pm\sqrt{y + 18}$