What is the answer to 9x + (-5x) ?

Hello people, i have a math question that i need with, me, i will give the correct one brainiest, and for the other correct people, a and 5 stars.

Idon’t understand! use slope intercept form to solve: through: (2,5) slope= undefined

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.