I need help please I need to get the right answer

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

The volume of a sphere is increased by 6%. calculate the corresponding percentage increased in it area.

1. ∠1 is complementary to ∠2 and ∠3 is complementary to ∠2. subtraction property of equality 2. m∠1 + m∠2 = 90 and m∠3 + m∠2 = 90 substitution 3. m∠1 + m∠2 = m∠3 + m∠2 definition of complementary 4. m∠1 = m∠3 given