Integer and rational operations 24+(-12)=​

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

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! )

B. jan surveyed her friends to find their favorite season. she recorded jhi ii for summer. how many people chose summer as their favorite season?