Given:
x - y = 9
3x = 6y
Solve for y:
-y = 9 - x Subtract x from both sides
y = -9 + x multiply by -1
y=x - 9 clean it up
Substitute y:
3x = 6 * (x - 9) multiply 6 into x and -9
Solve for X:
3x = 6x - 54 subtract 6x from both sides
3x - 6x = -54
-3x = -54 Divide by -3
x = 18
Substitute X:
y = 9 - 18
y = 9
We get:
x = 18 and y = 9
18 - 9 = 9
3(18) = 6(9)