Question

(3x -1 ) (x+1)- 3x(x+1)=7

Answer 1

• 
  `\bf x=-8`

Explanation:

`\bf (3x -1 ) (x+1)- 3x(x+1)=7`

Expand:-

`\bf 3x^2+2x-1-3x\left(x+1\right)`

`\bf 3x^2+2x-1-3x^2-3x`

Combine like terms:-

`\bf (3x^2-3x^2)+(2x-3x)-1`

`\bf -x-1=7`

Add 1 to both sides:-

`\bf -x-1+1=7+1`

`\bf -x=8`

Divide both sides by -1:-

`\bf \cfrac{-x}{-1}=\cfrac{8}{-1}`

`\bf x=-8`

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Hope this helps!

Answer 2

x = - 8

Explanation:

(3x - 1)(x + 1) - 3x(x + 1) = 7 ← factor out (x + 1) from each term

(x + 1)(3x - 1 - 3x) = 7

(x + 1)(- 1) = 7 ( multiply both sides by - 1 )

x + 1 = - 7 ( subtract 1 from both sides )

x = - 8