Plaeas

-7(1+5m)-29<300+7m     expand Left side

-7 - 35m - 29   <  300 + 7m    simplify by gathering 'like' terms

   -42m  < 336    divide by - 42   ( this reverses the <    to > )

      m  > 336/(-42)

       m > -8

$-7\left(1+5m\right)-29<300+7m$

 

$-35m-36<300+7m$

 

$-35m-36+36<300+7m+36$

 

$-35m<7m+336$

 

$-35m-7m<7m+336-7m$

 

$-42m<336$

 

$\left(-42m\right)\left(-1\right)>336\left(-1\right)$

 

$42m>-336$

 

$\frac{42m}{42}>\frac{-336}{42}$

 

 $m>-8$

 

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