Answer:
c
Explanation:
plug in 5x for y to get 5x+5x=30. combine to get 10x=30. divide by 10 on both sides to get x=3. sub that in for x. we know that y=5x, so if we plug in 3 for x, you get 5*3=y. 5*3 is 15, so y=15. the solution is (3,15) which is c