X + 3y=-12

5x - 3y=-6

How do you solve this situation by substitution

x + 3y = - 12

x = - 3y - 12

5 (-3y - 12) - 3y = - 6

-15y - 60 - 3y = - 6

-18y = 54

y = - 3

x + 3 (-3) = - 12

x - 9 = - 12

x = - 3

To solve this by substitution, you can take one of the equations and get a variable alone on one side, so:

x + 3y = - 12

x = - 3y - 12

Next, you can plug - 3y-12 in for the x values in the second equation to get:

5 (-3y - 12) - 3y = - 6

-15y - 60 - 3y = - 6

-18y = 54

y = - 3

And with the y value found, you can plug it back into the first equation to find x.

x + 3 (-3) = - 12

x - 9 = - 12

x = - 3