I only need question 18 and 20 done, thanks!

Use the x-intercept method to find all real solutions of the equation.x^3-10x^2+27x-18=0

Given f(x)= 9x+1 and g(x)=x^3, choose the expression (f*g)(x)

Do some research and find a city that has experienced population growth. determine its population on january 1st of a certain year. write an exponential function to represent the city’s population, y, based on the number of years that pass, x after a period of exponential growth. describe the variables and numbers that you used in your equation.