It looks like the first thing you have to find is their GCF, ya reckon ?
The factors of 56 are 1, 2, 4, 7, 8, 13, 28, and 56 .
the factors of 64 are; 1, 2, 4, 8, 16, 32, and 64 .
The common factors are 1, 2, 4, and 8 .
The greatest one is 8 .
56/8 = 7
64/8 = 8
56 plus 64 = (8 times 7) plus (8 times 8)
56 plus 64 = 8 times (7 plus 8) <== that's the answer
Check it out:
56 plus 64 = 120
8 times (7 plus 8) = 8 times 15 = 120 yay!