Question

What equation results from completing the square and then factoring?
x2 - 8x = 39
O A. (x-8)2 = 55
O B. (X-8)2 = 23
O C. (x-4)2 = 23
O D. (x-4)2 = 55

Answer 1

Answer:

$\large\boxed{D.\ (x-4)^2=55}$

Step-by-step explanation:

$(a-b)^2=a^2-2ab+b^2\qquad(*)\\\\\\x^2-8x=39\\\\x^2-2(x)(4)=39\qquad\text{add}\ 4^2=16\ \text{to both sides}\\\\\underbrace{x^2-2(x)(4)+4^2}_{(*)}=39+16\\\\(x-4)^2=55$

Answer 2

Answer: the answer is D

Step-by-step explanation: