Please answer correctly

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

Is ofat (-25, 0), (25, 0) co- (0, -15), (0, 15)?

What will be the end result for the taxpayer who filed his federal income tax return using the 1040ez form shown belowa he'll owe $173b he'll receive a refund of $173c he'll owe $3921d he'll receive a refund of $3921