Answer:
[tex]3x^2 - 15x + 21\\or\,\,3(x^2 -5x +7)[/tex]
Step-by-step explanation:
First we will find sum of [tex](-9x^2-10x)\,\, and\,\, (3x^2+3x+7)[/tex]
Adding the like terms:
[tex]= -9x^2-10x + 3x^2 +3x+7\\= -9x^2+ 3x^2 -10x+3x+7\\= -6x^2 - 7x +7[/tex]
Now subtract (-9x^2+8x-14) from (-6x^2 - 7x +7)
[tex]=(-6x^2 - 7x +7) - (-9x^2+8x-14)\\= -6x^2 - 7x +7 +9x^2-8x+14\\= -6x^2 +9x^2 - 7x -8x+7 +14\\= 3x^2 - 15x + 21\\=3(x^2 -5x +7)[/tex]
