How do you solve x+3y=-1, y=x+1?

1 Answer
Mar 3, 2018

For a problem like this you would use substitution method.

Explanation:

Since the problem already gives you the value of y (which is x + 1), you would use that information and apply it to the equation

x + 3y = -1

How you would do this is by replacing x + 1 (the value of y) into the original equation wherever you see y.

So:

x + 3y = -1

x + 3(x + 1) = -1

(Solve algebraically)

x + 3x + 3 = -1

4x + 3 = -1

4x = -4

x = -1

Now to find y as a number, you would plug in -1 as x and solve:

y = x + 1

y = -1 + 1

y = 0