3x + y = -2, [1]
x = y - 2 [2]
Since equation [2] is equal to 'x' we can simply put this equation into equation [1]:
So, take equation [1], 3x + y = -2
Put in equation [2], 3(y - 2) + y = -2
Now multiply out the brackets, 3(y) 3x(-2) + y = -2
3y -6 + y = -2
4y - 6 = -2
Now you can add 6 to both sides of the equation, 4y - 6 + 6 = -2 + 6
4y = 4
Now you can divide both sides of the equation by 4, (4y)/4 = 4/4
y = 1
So now you have the value for 'y' you can simply put this value into one of the original equations to find the value of 'x'.
So take equation [2], x = y - 2
Substitute in the value of y, x = 1 - 2
x = -1
So the solution to this system of equations is:
(-1, 1)