Answer:
12 1/4
Step-by-step explanation:
(7 + X) × 8 - 4 × X = 56
7 + X × 8 - 4 × X = 56
7 + 8X - 4 × X = 56
7 + 8X - 4X = 56
7 + 4X = 56
4X = 56 - 7
X = 49/4
X = 12 1/4