Which types of reasons are not valid in a mathematical proof?

A. unproven theorems

B. postulates

C. definitions

D. already-proven theorems

Eric's car has a gas tank that holds 21 liters. If Eric used up 2 decaliters of gas, how many liters of gas does he have left in the tank?

y = - 6x2 + 3x + 2 rewritten in vertex form

Alex has 100 balloons. He gives an equal number of balloons to each of his 5 friends. How many balloons should each friend get?

A recipe for making popcorn requires 2 tablespoons of butter for every cup of popcorn kernels. At this rate, how much butter is required if 1 cup of popcorn kernels are used? A. 3 tablespoons B. 5 tablespoons C. 2 tablespoons D. 6 tablespoons

Write a real world problem that involves a percent.

Dara spends $13.02 on sandals, $9.85 on shorts, and $15.20 on a hat. how much change does she recieve back from $50

Share £20 in the ratio 2:3

What landmarks are located in west India?

Why was Copernicus' work controversial? A. His invention of the printing press increased literacy and therefore threatened the political order. B. He called for an ideal society in which people share resources and devote time to education. C.

Before a race, you start 3 1/4 feet behind your friend. At the finish line you are 2 1/3 feet ahead of your friend. What is the change in distance between you and your friend?