Các bạn làm giúp mik với mik cần gấp

Bài `4:`

`a.`

`(-1005).(x+2)=0`

`<=>x+2=0`

`<=>x=-2`

Vậy `x=-2`

`b.`

`(8+x).(6-x)=0`

`<=>`\(\left[ \begin{array}{l}8+x=0\\6-x=0\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=-8\\x=6\end{array} \right.\) 

Vậy `x=-8` hoặc `x=6`

`c.`

`8x(5-x)=0`

`<=>`\(\left[ \begin{array}{l}8x=0\\5-x=0\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=0\\x=5\end{array} \right.\) 

Vậy `x=0` hoặc `x=5`

`d.`

`x^2-5x=0`

`<=>x(x-5)=0`

`<=>` \(\left[ \begin{array}{l}x=0\\x-5=0\end{array} \right.\)

`<=>`\(\left[ \begin{array}{l}x=0\\x=5\end{array} \right.\) 

Vậy `x=0` hoặc `x=5`

Bài `5:`

`a.`

`x+x+x+91=-2`

`<=>3x=-2-91`

`<=>3x=-93`

`<=>x=-31`

Vậy `x=-31`

`b.`

`-152-(3x+1)=(-2).(-27)`

`<=>-152-3x-1=54`

`<=>-3x=54+153`

`<=>-3x=207`

`<=>x=-69`

Vậy `x=-69`

`c.`

`(5x+1)^2=121`

`<=>`\(\left[ \begin{array}{l}5x+1=11\\5x+1=-11\end{array} \right.\) 

`<=>` \(\left[ \begin{array}{l}5x=10\\5x=-12\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=2\\x=\dfrac{-12}{5}\end{array} \right.\) 

Vậy `x=2` hoặc `x=-12/5`