Hello from MrBillDoesMath!
Discussion:
Given: (1/2) ( 4 + 8x) = 17 => multiply both sides by 2
4 + 8x = 17 * 2 = 34 (*) => divide both sides by 2
2 + 4x = 17 (**) => subtract 2 from both sides
4x = 17 - 2 = 15 (***) => divide both sides by 4
x = 15/4 (****)
Provided equations:
2 + 4x = 8.5 No cigar. Not equal to (**).
4x = 15 Yes, they are equal. This is (***)
4 + 8x = 34 Yes, they are equal. This is (*)
2 = 17 - 8x No cigar. 2 = 17-8x => 8x = 15 => x = 15/8 which is not
equal to (****)
Only the second and third choices above are equal.
Thank you,
MrB