Simplify the following:
x^2+x+3-2 (-x^2-2 x+7)+x^2+9
Grouping like terms, x^2+x+3-2 (-x^2-2 x+7)+x^2+9 = -(2 (-x^2-2 x+7))+(x^2+x^2)+x+(3+9):
-(2 (-x^2-2 x+7))+(x^2+x^2)+x+(3+9)
x^2+x^2 = 2 x^2:
-(2 (-x^2-2 x+7))+2 x^2+x+(3+9)
3+9 = 12:
-(2 (-x^2-2 x+7))+2 x^2+x+12
-2 (-x^2-2 x+7) = 2 x^2+4 x-14:
2 x^2+4 x-14+2 x^2+x+12
Grouping like terms, 2 x^2+2 x^2+4 x+x-14+12 = (2 x^2+2 x^2)+(4 x+x)+(-14+12):
(2 x^2+2 x^2)+(4 x+x)+(-14+12)
2 x^2+2 x^2 = 4 x^2:
4 x^2+(4 x+x)+(-14+12)
4 x+x = 5 x:
4 x^2+5 x+(-14+12)
12-14 = -2:
Answer: | 4x^2 + 5x - 2
