Question
Add $ \, \color{blue}{ x^2+4x-21 } \, $ and $ \, \color{orangered}{ 10-5x-4x^2 }$.
Answer
$$ \left( \color{blue}{x^2+4x-21} \right) + \left( \color{orangered}{10-5x-4x^2} \right) = -3x^2-x-11 $$
Explanation
Step 1: First we have to write polynomials in descending order.
$$ \begin{aligned} P(x) &= x^2+4x-21 \\ Q(x) &= -4x^2-5x+10 \\ \end{aligned} $$Step 2: Write second polynomial below the first one. Making sure like terms are lined up.
$$ \begin{array}{lrrr} & x^2 & 4x & -21 \\ \color{blue}{ + } & -4x^2 & -5x & 10 \\ \hline \end{array} $$Step 3: Combine like terms (add each column):
$$ \begin{array}{lrrr} & x^2 & 4x & -21 \\ \color{blue}{ + } & -4x^2 & -5x & 10 \\ \hline & -3x^2 & -x & -11 \end{array} $$This page was created using
Polynomial Operations Calculator