A number is 5 times bigger than a second number. Both these numbers added together must make 72. What is a system of equations for this?

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

The lengths of all sides of a triangle are integers when measured in decimeters. one of the sides has length of 1 dm and another of 3 dm. find the perimeter of the triangle.'

If y varies directly as x2 and y=6 when x=6, find the constant of variation.