The area of a rectangle is2x ^(2) - 7x - 4if the area is 45, what is the positive value for x

Question

the area of a rectangle is
`2x ^(2) - 7x - 4`if the area is 45, what is the positive value for x

Answer 1

The given expression is,

`2x^2-7x-4=45`

As the area is equal to 45 and equating the areas.

`\begin{gathered} 2x^2-7x-49=0 \\ x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a} \\ \text{ =}\frac{\text{7}\pm\sqrt[]{49+4*2*49}}{2*2} \\ =(7\pm21)/(4) \\ =7 \end{gathered}`

(taking positive values)

The answer is 7