5(X + 6) + 4(3X - 7) (I'll use 'X' for the letter x, and 'x' for multiplication)
So first you need to multiply out the brackets, this means that
5(X + 6) + 4(3X - 7) = 5X + 5x6 + 4x(3X) + 4x(-7) = 5X + 30 + 12X - 28 = 17X + 2
So the final simplified equation is 5(x + 6) + 4(3x - 7) = 17X + 2