This week in math I have learned how to solve and sub with linear equations.
ex: y=3x-7 and y=-x+9
first, I would sub in -x+9 for y of y=3x-7
-x+9=3x-7
next I would subtract 9 from each side
-x+9=3x-7
-9 -9
then I would subtract 3x from each side
-x=3x-16
-3x -3x
Then I would divide each side by -4
-4x/-4=-16/-4
Which would make x=4. Now I would imput 4 into y=-x+9
Now to solve for y
y=-x+9
y=-(4)+9
y=5.
to double check my answer I would do the same with the other question:
y=3x-7
y=3(4)-7
y=12-7
y=5
That is how you do it.