Triangle qrs is a right triangle with the right angle at vertex r. the sum of m∠q and m∠s must be

Can any one me with the answers to these questions asap?

Do,h = (7, 9) (14, 18) the scale factor is

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.