If 6 cost $60, how much do 8 cost​

Question and answers are in the attached picture. you so much in advance.

Sum is 17 and their difference is 3

For the quadratic function [tex]y=(x+4)^2-1[/tex] , do the following: a) rewrite the function in the standard form, b) rewrite the function in intercept form, c) find the vertex, d) find the y-intercept, e) find the x-intercepts.