Answer:
x = 4 or x = -3
Step-by-step explanation:

Take square both the sides,

x² - x - 12 = 0
x² - 4x + 3x - 3*4 =0
x*(x - 4) + 3*(x - 4)= 0
(x- 4 )(x+3) =0
x -4 =0 or x + 3 = 0
x = 4 or x = -3
X is 16 so turn everything into a equation
quadratic formula:
x = <u>-b ± √(b² - 4ac)</u>
2a
7x² - x = 7
subtract 7 from both sides:
7x² - x - 7 = 0
plug values into the quadratic formula:
x = <u>-(-1) ± √((-1)²- 4(7)(-7))</u>
2(7)
simplify:
x = <u>1 ± √(197)</u>
14