Step 1: First we have to write polynomials in descending order.

$$ \begin{aligned} P(x) &= 16x+7 \\ Q(x) &= 9x+5 \\ \end{aligned} $$

Step 2: Write second polynomial below the first one. Making sure like terms are lined up.

$$ \begin{array}{lrr} & 16x & 7 \\ \color{red}{ - } & 9x & 5 \\ \hline \end{array} $$

Step 3: Change ALL the signs in the second row.

$$ \begin{array}{lrr} & 16x & 7 \\ \color{red}{ - } & -9x & -5 \\ \hline \end{array} $$

Step 4: Combine like terms (add each column):

$$ \begin{array}{lrr} & 16x & 7 \\ \color{red}{ - } & -9x & -5 \\ \hline & 25x & 12 \end{array} $$

Polynomial Operations Calculator