( 8 X 18 - 5 X 18 - 18 X 3 ) X X + 2 X X = 8 X 7 + 24 ( 8 X 18...

24. ( 8 x 18 - 5 x 18 - 18 x 3 ) x X + 2 x X = 8 x 7 + 24