Răspuns:
[tex] \frac{ {x}^{2} - 18x + 81}{ {x}^{2} - 81 } = \frac{ {(x - 9)}^{2} }{(x - 9)(x + 9)} = \frac{x - 9}{x + 9} [/tex]
b),(x-6)(x+6)/(x-6)^2=(x+6)/(x-6)
c)(x-8)(x+8)/(x+8)^2
d)(x+5)^2/x(x-5)(x+5)=(x+5)/x(x-5)
e)x(x-7)(x+7)/x(x+7)^2=(x-7)/(x+7)
f)x^2(x-10)(x+10)/x(x+10)^2=x(x-10)/(x+10)
11.a)(x-3)(x+3)/(x^2+5x+15-9)=
(x-3)(x+3)/(x^2-9+5x+15)=
(x-3)(x+3)/(x+3)(x-3+5)=(x-3)/(x+2)
domeniul de definiție R-{-2}
b)(x^2-25)/(x+6)(x+5)=(x-5)/x+6)
D:R-{-6}
c)(x+3)^2/(x+3)(x+4)=(x+3)/(x+4)
D:R-{-3;-4}
d)(x-2)(x-3)/(x-2)^2=(x-3)/(x-2)
D:R-{2]
e)(x+4)^2/(x+4)(x+3)=(x+4)/(x+3)
D:R-{-3}
f)
