Which expression represents the number of possible combinations of n items taken r at a time?

This is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 5 terms.

Solve the equation. 2x - 8(x+1)= 6(2x - 3)

Find the vertex for the parabola given by the function ƒ(x) = −3x2 − 6x.