Question

Rezolvati in R ecuatia   (5x-1)²-(x-6)(x+8)=85

Answer 1

Ridicam la patrat si efectuam inmultirea celor doua paranteze:
$25x^2-10x+1-x^2-8x+6x+48=85$

24x²-12x-36=0 impart la 12

2x²-x+3=0

$\Delta=b^2-4ac=25$

$x_{1;2}=\dfrac{-b\pm\sqrt{\Delta}}{2a}=\dfrac{1\pm5}{4}\ si \ de\ aici\ x_1=\dfrac32;\ \ x_2=-1$