(13 points & to get BRAINLIEST, plz give a good explanation so I can improve) Indications:
Ignore my work for number 1, I need help with number 2. I must submit before 11:59 and it would be really appreciated to get an explanation, not only the answers to the questions.

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

What are the soultion(s) to the quadratic equation 40- x^2=0

Find the volume of the solid whose base is the region bounded by f(x), g(x) and the x-axis on the interval [0, 1], and whose cross-sections perpendicular to the y-axis are squares. your work must show the integral, but you may use your calculator to evaluate it. give 3 decimal places for your answe