Y equals x plus 6 and Y equals -2x minus 3 using substitution?

Answer 1

y = x + 6

y = -2x - 3

First we'll solve for y.

We need to get x by itself.

y = x + 6

Minus the 6, so:

y - 6 = x

Substitute x for (y - 6) and Solve the second equation (y = -2x - 3)

y = -2(y - 6) - 3

Distribute the Negative 2 to the y and -6

The two negatives become a positive 6. The y becomes negative 2y.

y = -2y + 12 - 3

Add the -2y to other y, and do 12 - 3

3y = 9

Divide out the 3

y = 3

Now solve for x, using the first equation. Replace the y for (3) and solve.

y = x + 6 when the y is substituted...

3 = x + 6

Minus the 6

-3 = x

Check your work:

Replace the y for (3) and x for (-3). Make sure it works.

y = x + 6 when substituted is..

3 = -3 + 6

Add -3 and 6

3 = 3

TRUE.

Now do the second equation

y = -2x - 3 when substituted is...

3 = -2(-3) - 3

Multiply -2 and -3 to get positive 6

3 = 6 - 3

Minus 3 from 6 to get 3

3 = 3

TRUE

X = -3

Y = 3