change the equation, x - y = -3, to isolate x or y and plug that new equation into the equation 2x + 3y = 4
I changed it to: x = y - 3
so
2(y - 3) + 3y = 4
2y - 6 + 3y = 4
5y - 6 = 4
5y = 4 + 6
5y = 10
y = 10/5
y = 2
then you plug that 2 into the equation x = y - 3 to get the value of x
x = (2) - 3
x = -1
you can check this by plugging the x and y values into the equation 2x + 3y = 4
2(-1) + 3(2) = 4
-2 + 6 = 4
4 = 4
hope this helps :)