Question

(x+5)^2+(x+6)-(x-6)=(x+5)^2+5
Culegerea: gheba
Pag: 31
Ex:2

Answer 1

Răspuns:

a) (x+2)(2x-3)=2x²+4x-3x-6=2x²+x-6

E(x)=[(x-6)/(x²-25) - x/(5-x) - 2/(x+5)]:(2x²+x-6)/(x²-25)=

=[(x-6)/(x-5)(x+5) + x/(x-5) - 2/(x+5)] ×(x-5)(x+5)(x+2)(2x-3)=

={[(x-6)+x(x+5)-2(x-5)]/(x-5)(x+5)  ×(x-5)(x+5)/(x+2)(2x-3)=

=(x-6+x²+5x-2x+10)/(x+2)(2x-3)=

=(x²+4x+4)/(x+2)(2x-3)=

=(x+2)²/(x+2)(2x-3)=

=(x+2)/(2x-3)

c)(x+2)/(2x-3)  si   (2x-3)/(2x-3) ⇒

(2x+4)/(2x-3) si (2x-3)/(2x-3)

scadem ⇒7/2x-3⇒2x-3∈D7

D7={+1;-1;-7;+7}  ⇒2x-3=1⇒x=2

                                  2x-3=-1⇒x=1

                                  2x-3=7⇒x=5

                                  2x-3=-7 ⇒x=-2

sper ca te-am ajutat