Question

1. $3x - 7x^{2} + 6x + 3x^{2} - 7$

Explanation:

Step1: Group like terms

$(-7x^2 + 3x^2) + (3x + 6x) - 7$

Step2: Combine $x^2$ terms

$-7x^2 + 3x^2 = -4x^2$

Step3: Combine $x$ terms

$3x + 6x = 9x$

Step4: Write simplified expression

$-4x^2 + 9x - 7$

Answer:

$-4x^2 + 9x - 7$