Could anyone answer #5,6,7. Thank you!

At which value in the domain does f(x) =0?

Solve by any method (graphing, substitution or linear combination)y = x - 82x + 3y = 1a) (2, -6)b) (5, -3)c) (4, -4)d) (0, -8)i figured it out. the answer is (5, -3)

Calculate the missing value. round the answer to on decimal place. start with 70, increase it by 21%, and end up with