Is m=-3 the solution to m+1=-2m-8

Abox of chocolates costs $7. which equation relates the number of boxes sold (x) and total cost of the boxes sold (y)?

What is the distance between the points (2 -3) and (-6 4) on the coordinate plane

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! )