Y= 5x + 7
x = 8
a. (0, 8)
b. (8, 15)
c. (0, 7)
d. (8, 47)

The answer is: [D]:  (8, 47) .

Explanation:

Since the answer choices are written in the format of (x, y), and since we are given:  " x = 8 " ;  we look at the answer choices given and know that the answer will be either: 1) Answer choice "B" ; or 2) Answer choice "D".

Given the equation: y = 5x + 7 ; and given: " x = 8 " ;  

We know our value "x"; and we plug in that value for "x" to solve for "y" ; as follows:

y = 5x + 7 ;  

y = (5*8) + 7 ;

y = (40) + 7 = 47.

So, x = 8; y = 47.  This corresponds with Answer choice: [D]: (8, 47).