Question

ajutatima la punctul 5 va rog

Answer 1

Ex.3
$\frac{4}{ x^{2} -9}- \frac{2}{x+3} = \frac{4}{(x-3)(x+3)} - \frac{2}{x+3}$
Aducem fractia a doua la acelasi numitor:
⇒$\frac{4}{(x-3)(x+3)}- \frac{2(x-3)}{(x-3)(x+3)} = \frac{4-2(x-3)}{(x-3)(x+3)}= \frac{4-2x+6}{(x-3)(x+3)}= \frac{10-2x}{(x-3)(x+3)}=$=$\frac{2(5-x)}{(x-3)(x+3)}$

Ex.4
$\frac{ x^{2}-4 }{ x^{2}+2x+1 } : \frac{x+2}{x+1}= \frac{(x-2)(x+2)}{x+1}* \frac{x+1}{x+2}$ se simplifica prin x+2 si x+1⇒$\frac{x-2}{x+1}$

Ex.5
Numaratorul se poate scrie restrans: $(x-2y)^{2}$

⇒$\frac{ (x-2y)^{2} }{x-2y}+x+2y=x-2y+x+2y=2x$