To eliminate y, double the second equation and add it to the first.
2(3x + 2y) + (2x - 4y) = 2(18) + (-4)
8x = 32
x = 4
You can solve for y by substituting this value into either equation.
2(4) - 4y = -4
12 - 4y = 0
3 - y = 0
3 = y
2(3x + 2y) - 3(2x - 4y) = 2(18) - 3(-4)
6x + 4y - 6x + 12y = 36 + 12
16y = 48
y = 3
2(3x + 2y) + (2x - 4y) = 2(18) + (-4)
8x = 32
x = 4
You can solve for y by substituting this value into either equation.
2(4) - 4y = -4
12 - 4y = 0
3 - y = 0
3 = y
The solution is (x, y) = (4, 3).
You can eliminate x by multiplying the first equation by 3 and subtracting that from twice the second equation. The idea of doing the multiplications is to make the coefficients of the x terms in the product be the same. Then, when you do the subtraction, they cancel.2(3x + 2y) - 3(2x - 4y) = 2(18) - 3(-4)
6x + 4y - 6x + 12y = 36 + 12
16y = 48
y = 3