Ex.3
[tex] \frac{4}{ x^{2} -9}- \frac{2}{x+3} = \frac{4}{(x-3)(x+3)} - \frac{2}{x+3} [/tex]
Aducem fractia a doua la acelasi numitor:
⇒[tex] \frac{4}{(x-3)(x+3)}- \frac{2(x-3)}{(x-3)(x+3)} = \frac{4-2(x-3)}{(x-3)(x+3)}= \frac{4-2x+6}{(x-3)(x+3)}= \frac{10-2x}{(x-3)(x+3)}= [/tex]=[tex] \frac{2(5-x)}{(x-3)(x+3)} [/tex]
Ex.4
[tex] \frac{ x^{2}-4 }{ x^{2}+2x+1 } : \frac{x+2}{x+1}= \frac{(x-2)(x+2)}{x+1}* \frac{x+1}{x+2} [/tex] se simplifica prin x+2 si x+1⇒[tex] \frac{x-2}{x+1} [/tex]
Ex.5
Numaratorul se poate scrie restrans: [tex] (x-2y)^{2} [/tex]
⇒[tex] \frac{ (x-2y)^{2} }{x-2y}+x+2y=x-2y+x+2y=2x [/tex]
