Question

Rezolvati:
a)(2x+3)²-2(x-1)(x+1)+15=3(2-x)²-(x+1)-11

Answer 1

Rezolvare :
(2x+3)²=2x²+2·2x·3+3²⇒2x²+12x+9
-2(x-1)=-2x+2
(-2x+2)(x+1)= -2x²-2x+2x
3(2-x)²=3(4+4x+x²)⇒12+12x+3x²
-(x+1)=-x-1
Din toate astea ⇒ecuatia : 2x²+12x+9-2x²-2x+2x+2+15=12+12x+3x²-x-1-11 
Se trece totul intr-o parte si egalam cu 0 : 2x²+12x+9-2x²-2x+2x+2+15-12-12x-3x²+x+1+11=0
⇒-3x²+x+26=0
a=-3
b=1
c=26 din a. b , c ⇒Δ=b²-4·a·c⇒Δ= 1- 4·(-3)·26⇒Δ=313