Question

Solve the system using substitution: X+Y=5 Y=X - 9

Answer 1

Answer:

x = 7

y = -2

Step-by-step explanation:

There are 2 equations. The substitution method takes one equation and puts it into the other and solves for 1 variable. Then you take that answer and put into any one equation and solve for the other variable.

Since equation #2 is already given for y = SOMETHING, we take that something and put it into "y" of the 1st equation. Shown below:

$x+y=5\\x+(x-9)=5\\x+x-9=5\\2x=5+9\\2x=14\\x=\frac{14}{2}\\x=7$

We got x = 7

Now, we know from Equation #2, y = x - 9, so

y = x - 9

y = 7 - 9

y = -2

Hence,

y = -2

In coordinate pair, the answer is (7, -2)