Question

Solve: 2y + 5x=30 y = 3x + 4

Answer 1

Replace the second equation y=3x+4 into the first one:
2(3x+4)+5x=30
Now solve for x:
6x+8+5x=30
11x=30-8
11x=22
x=22/11
x=2
Finally, replace x=2 into y=3x+4
y=3*2+4
y=6+4 = 10
So the anwer is x=2, y=10