Question

X²+8x-84=0

Formúla General ​

Answer 1

`x_(1) =-14\\\\x_(2) =6`

Explanation:

`x^(2) +8x-84=0\\\\x=\frac{-b \pm \sqrt{b^(2)-4ac } }{2a} \\\\a=1; \: \: b=8; \: \: c=-84\\\\x=\frac{-8 \pm \sqrt{8^(2)-4 \cdot 1 \cdot (-84) } }{2 \cdot 1}=(-8 \pm √(400 ) )/(2)=(-8 \pm20)/(2) =-4 \pm 10\\\\x_(1) =-14\\\\x_(2) =6`