Suppose the measure of B is 89 degrees. Which other angles must measure 89 degrees? How do you know?

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a

Simplify (8x2 − 1 + 2x3) − (7x3 − 3x2 + 1). −5x3 + 11x2 − 2 5x3 − 11x2 + 2 x3 + 2x2 + x3 x3 − 2x2 − x3

Alice is paying her bill at a restaurant. but tax on the cost of a male is 5%. she decides to leave a tip 20% of the cost of the meal plus the tax