question_answer

If A =\[2+4x+8{{x}^{2}}\],B =\[-3-5x+{{x}^{2}}\], C = 1 + \[3x-7{{x}^{2}}\]find A + B + C

Answer:

\[A=2+4x+8{{x}^{2}}\] \[B=-3-5x+{{x}^{2}}\] \[C=1+3x-7{{x}^{2}}\] A+B+C=?                                          A+B+C=\[\left( 2+4x+8{{x}^{2}} \right)+\left( -3-5x+{{x}^{2}} \right)\]   \[+\left( 1+3x-7{{x}^{2}} \right)\] \[=2+4x+8{{x}^{2}}-3-5x+{{x}^{2}}+1+3x-7{{x}^{2}}\] \[={{x}^{2}}+1-7)4-x(4-5+3)+2-3+1\] \[=\text{ }2{{x}^{2}}+2x+0\]                                       = \[2{{x}^{2}}\]+2x = 2x(x + 1).