Find the constant of proportionality
Using substitution:
first you have to express one variable in terms of the other, in this we can express y in terms of x:
Since both expressions are equal to y, you have to equal both expressions like this:
Now you can solve the equation:
Knowing x=10, you can use any of the expressions we found before to find y. In this case I'm going to use y= -x+9 because it's simpler but boy should give you the same result
So, the answer is x=10 and y=-1
First you need to combine like terms
7-3x= 5x+13
step 1 add 3x
7=8x+13
step 2 subteact 13
-6=8x
step 3 divide both sides by two
x=-3/4