When an equation contains fractions, what should you do before getting the variables together on one side?

Which expression gives the exact value of x?

Examine this system of equations. what integer should the second equation be multiplied by so that when the two equations are added together, the x term is eliminated? 3/4x+1/7y=6 1/8x-3/5y=16

Which of the following is another way to express the difference between -5 and 8?