Question

Factor by grouping

$x^2+7x-3x-21$

Short answer

Factor is:$x^2+7x-3x-21=(x+7)(x-3)$

Step-by-step solution

Step 1. Given information

given expression,

$x^2+7x-3x-21$

Step 2. Grouping given expression,  

$x^2+7x-3x-21=(x^2+7x)(-3x-21)$

Step 3. Factorize 

$$\begin{gathered} (x^2+7x)(-3x-21)=x(x+7)-3(x+7) \\ =(x+7)(x-3) \end{gathered}$$

Therefore, the factor of the given expression is$(x+7)(x-3)$