Please help me

if you can't read it it says
-138=-6(6b-7)

Witch represents the inverse of the function f(x)=1/4x-12

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)