Simplify the expression by combining like terms. 12d−34d+3f−2f
Enter your answer as an expression, like this: 42x+53

Answer this 30 points and brainliest!

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?

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?