Can someone tell me the answer please. they were covering this while I was in quarantine

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

Afamily of five rents a kayak and splits the total time, k, equally. each family member spent less than 25 minutes kayaking. which values can be used to complete the math sentence below so that it accurately represents the situation? intro done

Which of the binomials below is a factor of this exression? 16x^2+40xy+25y^2 a.4x-5y b. 2x-5y c.4x+5y d.2x+5y