When solving a system of equations, jared found y = x + 10 for one equation and substituted x + 10 for y in the other equation. nicole found x = y – 10 for the same equation and substituted y – 10 for x in the other equation. who is correct? explain.

Both of them are correct depends on what they variable are they trying to get.
Jared is trying to get the value of y in terms of x using the second equation. On the other hand, Nicole is trying to get the value of x in terms of y using the second equation. both of them will end up getting the same thing.

Answer

Both are correct.

Explanation
The both equations are the same.
When we say that y=x+10, we can make x the subject of the formula and get;
y=x+10
y-10=x
x=y-10.

If the substitution is done correctly, that is x+10 for y and y-10 for x in the other equation then, both would be correct.