the common denominator of 5/6 and 7/8 is 24, so multiply both sides of the equation (every term) by 24:
24(5/6)x + 24(2) = 24(7/8)
the denominators will cancel out so you have:
4(5x) + 48 = 3(7)
do the multiplication:
20x + 48 = 21
fractions have been eliminated, and if you want to continue to solve:
20x = -27
x = -27/20
