Question

Solve for x, where x > 0 and 84x(x + 2) = 90-13x. Express your answer as a simplified common fraction.

Answer 1

84x(x+2) = 84x² + 168x

84x² + 168x = 90 - 13x

84x² +181x - 90 = 0

bhaskara formula

`\frac{-181+-\sqrt{181^(2)- 4.84.(-90) } }{168 } }`

`(-181+-√(32.761 +30.240) )/(168)`

`(-181+-251)/(168)`

since its a positive number, we can't use the minus

so,
`(70)/(168)`

they're both dividable by 14, so

x =
`(5)/(12)` is your answer

hope it helps :)