Răspunsuri

2014-09-21T18:00:42+03:00
 (x-2)^{2} + (x+1)^{2} = 17
 x^{2} -2*x*2+ 2^{2} + x^{2} +2*x*1+ 1^{2} =17
2 x^{2} -2x+5=17
2 x^{2} -2x-12=0
x^{2} -x-6=0
Calculam discriminantul Δ= b^{2} -4ac, unde a=1, b=-1, c=-6, deci
 Δ= (-1)^{2} -4*1*(-6)=1+24=25>0
Solutiile:  x_{1}= \frac{-b+ \sqrt{delta} }{2a}  = \frac{1+5}{2}=3 si 
x_{2}= \frac{-b- \sqrt{delta} }{2a}  = \frac{1-5}{2}=-2 .