Whats 5a - 2a + 9 ?
could someone add how you got the answer to ?

The volume of gas a balloon can hold varies directly as the cube of its radius. imagine a balloon with a radius of 3 inches can hold 81 cubic inches of gas. how many cubic inches of gas must be released to reduce the radius down to 2 inches?

Bring the fraction a/a-4 to a denominator of 16-a^2

Simplify. 3(4+4x) (type your answer in with no spaces)