What is the first step in evaluating this expression? 15 + 20 ÷ (10 – 7) + 12

a
Subtract 7 from 10.
b
Divide 20 by 10.
c
Add 15 and 20.
d
Add 7 and 12.

Thw answer is a
parenthesis first then the rest

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!