Simplify the polynomials by combining like terms 3x 5x 4x

Hello! Combining like terms is just a fancy way of saying add all these numbers together. As long as numbers have the same variable (in this case x) and the same exponent (they don't have any in this case), you can add them together like normal. So! 3x + 5x + 4x is the same as 3+5+4. Your simplified polynomial is 12x. Good luck with the math homework!