Question

2x^2-5x-25=0

Quadratic formula

Answer 1

`x = 5 \: and \: - 2.5`

Explanation:

`2x {}^(2) - 5x - 25 = 0`

`a = 2 \: \: \: b = - 5 \: \: \: c = - 25`

`x = \frac{ - b \frac{ + }{} \sqrt{(b) {}^(2) - 4(a)(c)} }{2(a)}`

`x = \frac{ - ( - 5) \frac{ + }{} \sqrt{( - 5) {}^(2) - 4(2)( - 25) } }{2(2)}`

`x = \frac{5 \frac{ + }{} √(25 + 200) }{4}`

`x = \frac{5 \frac{ + }{} √(225) }{4}`

`x = \frac{5 \frac{ + }{}15 }{4}`

`x = (5 + 15)/(4) = (20)/(4) = 5`

`x = (5 - 15)/(4) = ( - 10)/(4) = - (5)/(2) or - 2.5`