Question

Im doing systems of equations and its 2x+2y=16

3x-y=4
and i found x is 36 and y is -28 but when i plug them in to check my work it is correct on the top equation but not on the bottom one. What am i doing wrong?

Answer 1

x=3, y=5 This means the point would be (3,5)

Explanation:

As I am unable to see your work, I am unable to tell you what you did wrong, but I hope you can notice what was wrong by comparing your work to mine

We are given the equations

`2x+2y=16\\3x-y=4`

The first thing we need to do is solve one of them for a variable and use substitution. I chose the second equation

`3x-y=4\\\\y=3x-4`

Now we can substitute in this equation for y

`2x+2y=16\\\\2x+2(3x-4)=16\\\\2x+6x-8=16\\\\8x=24\\\\x=3`

Now that we have the value for x, we can plug it into the second equation to easily find y.

`y=3x-4\\\\y=3(3)-4\\\\y=9-4\\\\y=5`

Finally, we can plug x and y into the first equation in order to check to make sure it works for the other equation

`2x+2y=16\\\\2(3)+2(5)=16\\\\6+10=16\\\\16=16`