10 POINTS! need help with one quadratic question

21. The quadratic equation 2x^2-16x-15=0 is rewritten as (x-p)^2=q. What is the value of q?
A. 47/2
B. 15/2
C. 143/2

2x^2 - 16x - 15 = 0
==>2(x^2 - 8x) = 15
==> (x^2 -8x + 16) -16 = 15/2
==> (x - 4)^2 = 47/2

2x^2 -16x = 15

DIVIDE BY 2

x^2 -8x = 15/2

ADD 16

x^2 -8x +16 = 15/2 +16 = 47/2

( x- 4)^2 = 47/2

q = 47/2

Answer is A )