Алгебра: Помогите решить ! СРочно нужно !!

2. $\frac{(x+y)^{2}-(x-y)^{2}}{x^{2} -y^{2} }* \frac{x^{2} -y^{2} }{xy} = \frac{(x+y-x+y)(x+y+x-y)}{xy}= \frac{2x*2y}{xy}=4$

3. $\frac{c^{2} }{(c-5)^{2}}* \frac{-1(c+5)(c-5)}{5(c+5)}+ \frac{c}{c-5}= \frac{-c^{2}+5c}{5(c-5)} = \frac{-c(c-5)}{5(c-5)}=- \frac{c}{5}$

4. ОДЗ: x≠0 и x≠3
$\frac{x}{3-x}= \frac{6}{x}-1$
$\frac{x}{3-x}= \frac{6-x}{x}$
x²=18-3x-6x+x² ⇒ 9x=18 ⇒ x=2