First solve the first equation for 'y'
3x - y = 4 subtract 3x from both sides
-y = -3x + 4 divide both sides by -1
y = 3x - 4 Now take this equation and substitute into the second equation:
5x + 3y = 9
5x + 3(3x - 4) = 9
5x + 9x - 12 = 9
14x - 12 = 9
14x = 9 + 12
14x = 21
x =
or 1.5
Now substitute this value for 'x' into either of the first two equations to find 'y'
I'll use the equation
y = 3x - 4
y = 3(1.5) - 4
y = 0.5
So your solution is (1.5, 0.5)
3x - y = 4 subtract 3x from both sides
-y = -3x + 4 divide both sides by -1
y = 3x - 4 Now take this equation and substitute into the second equation:
5x + 3y = 9
5x + 3(3x - 4) = 9
5x + 9x - 12 = 9
14x - 12 = 9
14x = 9 + 12
14x = 21
x =
Now substitute this value for 'x' into either of the first two equations to find 'y'
I'll use the equation
y = 3x - 4
y = 3(1.5) - 4
y = 0.5
So your solution is (1.5, 0.5)