HELPP PLSS 7TH GRADE

Which expressions are equivalent to -6 + 3m

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! )

Hurry im being timed the graph of f(x)=x^3-3x^2+4 is shown based on the graph how many distinct real numbers solutions does the equation x^3-3x^2+4=0 have