200
Step-by-step explanation:
1/5x -2/3y =30
Plug in 15 for y.
x-(15)= 30
2/3x of 2/3(15) is 10.
1/5x -10-30
Add 10 to each side.
1/5x = 40
Divide each side by 1/5.
(dividing by a fraction is the same as multiplying by its reciprocal...flip 1/5...*5)
x=200