Question

Elnaz rewrote the equation xto the power of 2 – 6x – 18 = 0 so that she can solve by completing the square. Which equation did she write? A. (x – 3)to the power of 2 = – 9 B. (x – 3)2 to the power of 2 = 18 C. (x – 3)to the power of 2 = 27 D. (x – 3)to the power of 2 2 = 54

Answer 1

x^2 − 6x − 18 = 0
=> x^2 − 6x = 18
Complete the square: add (−6/2)^2 = 9 to both sides:
x^2 − 6x + 9 = 18 + 9 = 27
So (x − 3)^2 = 27 — answer C.