Question

Efectuaţi:
2
X +16x=225

Answer 1

x^2+16x=225
x^2+16x-225=0

$\Delta=b^2-4ac=16^2-4*(-225)*=256+900=1156$

$x_1= \frac{-b+\sqrt{\Delta} }{2a}= \frac{-16+ \sqrt{1156} }{2} = \frac{-16+34}{2}=12$

$x_1= \frac{-b-\sqrt{\Delta} }{2a}= \frac{-16-\sqrt{1156} }{2} = \frac{-16-34}{2}=-25$

Answer 2

x²+16x-225=0
D=b²-4ac
D=16²-4•1•(-225)=256+900=1156=34²>0
x1=-b-√D/2a=-16-√34²/2•1=-16-34/2=-50/2=-25
x2=-b+√D/2a=-16+√34²/2=-16+34/2=18/2=9