How do you convert fractions to decimals 5/7

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)

Savannah is painting a striped background for a mural on a wall that is 1515 yards long. she wants a total of 9696 stripes that are all the same width. which calculation should savannah use to decide how wide to make each stripe?

Evaluate the expression for the given value of the variable. ∣-4b-8∣+∣-1-b^2 ∣+2b^3 ; b=-2