In general, what would every child function have in common with the parent function f(x)=x ?

Precalculus question, image attached.

Drag each expression to the correct location on the solution. not all expressions will be used. consider the polynomial 8x + 2x2 - 20x - 5. factor by grouping to write the polynomial in factored form.

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )