Question

The numerical difference of the roots of x‌2-7x-9=0?

Answer 1

Answer.

Given,

${x}^{2} - 7x - 9 = 0$

D = b² – 4ac

where,

$a = 1 \\ b = - 7 \\ c = - 9$

So, D = (–7)² – 4 × 1 × (–9)

= 49 + 36 = 85

By quadratic formula,

$x = \frac{ - b \: ± \: \sqrt{D \: } }{2a}$

$⇒ x = \: \frac{ - ( - 7) \: \: ± \sqrt{85} }{2 \times 1}$