15x^2 − 4x + x^2 + 9x − x − 6x^2 = ?First you can break up the question and sort out the x^2 part of the equation to make it easier: 15x^2 + x^2 − 6x^2 = 10x^2Then you are left with solving the second part of the equation which is: -4x + 9x - x = 4xWhen these two sections are then combined to complete the equation you get: = 10x^2 + 4xShowing that 15x^2 − 4x + x^2 + 9x − x − 6x^2 = 10x^2 + 4x