Question

2x squares plus 5x plus 9 equals 0 using quadratic formula

Answer 1

x = -
`(5)/(4)` +
`(√(47) )/(2)` i or -
`(5)/(4)` -
`(√(47) )/(2)` i

x = -1.25 + 3.43 i or - 1.25 - 3.43 i

Explanation:

solve 2x² + 5x + 9 = 0 using quadratic formula

The quadratic formula is;

x = -b ±√b² - 4ac / 2a

a = 2 b = 5 and c= 9

We can now proceed to insert the values into the formula;

x = -5 ± √5² - 4(2)(9) / 2(2)

x = -5±√25 -72 / 4

x = -5 ± √-47 / 4

x = -
`(5)/(4)` ±
`\sqrt{(47)/(4) }` .
`√(-1)`

But
`√(-1)` = i

x = -
`(5)/(4)` ±
`\sqrt{(47)/(4) }` . i

=-
`(5)/(4)` ±
`(√(47) )/(2)` i

x = -
`(5)/(4)` +
`(√(47) )/(2)` i or -
`(5)/(4)` -
`(√(47) )/(2)` i

x = -1.25 + 3.43 i or - 1.25 - 3.43 i