How to solve 2/3 of 2/3

How do i work this problem out using the equation a=pe^rt

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28

The input to the function is x and the output is y. write the function such that x can be a vector (use element-by-element operations). a) use the function to calculate y(-1.5) and y(5). b) use the function to make a plot of the function y(x) for -2 ≤ x ≤ 6.