Tap the blue circles to see an explanation.
$$ \begin{aligned}(x+h+2)(x-1)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}x^2-x+hx-h+2x-2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}hx+x^2-h+x-2\end{aligned} $$ | |
① | Multiply each term of $ \left( \color{blue}{x+h+2}\right) $ by each term in $ \left( x-1\right) $. $$ \left( \color{blue}{x+h+2}\right) \cdot \left( x-1\right) = x^2-x+hx-h+2x-2 $$ |
② | Combine like terms: $$ x^2 \color{blue}{-x} +hx-h+ \color{blue}{2x} -2 = hx+x^2-h+ \color{blue}{x} -2 $$ |