Question

Solve the equation by factoring. 2x^2 = 28 – x

x = –3.5 or x = 4
x = 2 or x = –7
x = –2 or x = 7
x = –4 or x = 3.5

Answer 1

The value of x = 3.5 or -4

Explanation:

=> 2x² = 28 – x

=> 2x²+ x - 28 = 0

=> 2x² + 8x - 7x - 28 = 0

=> 2x ( x + 4 ) - 7 ( x + 4 ) = 0

=> (2x - 7 ) ( x + 4 )

=> x = 7/2 = 3.5 or x = -4

Answer 2

x = –4 or x = 3.5

Explanation:

`2x^(2)=28-x\Longleftrightarrow 2x^(2)+x-28=0`

`\Longleftrightarrow 2x^(2)-7x+8x-28=0`

`\Longleftrightarrow x(2x-7)+4(2x-7)=0`

`\Longleftrightarrow (2x-7)(x+4)=0 \ \ \ \ \text{factor out} \left( 2x-7\right)`

`\Longleftrightarrow 2x-7=0 \ \ or\ x+4=0\ \ \ \ \text{(zero product rule)}`

`\Longleftrightarrow x=(7)/(2) \ \ or\ x=-4`