I need help with this problem

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

The angle of elevation from point a to the top of a cliff is 38 degrees . if point a is 80 feet from the base of the cliff , how high is the cliff ?

If f(x) = 3x-2 and g(x) =2x+1 find (f-g)(x)