Помогите пожалуйста решить 573 и 574

573
1) $( \frac{a}{a+1} + \frac{a+1}{a+1} ):( \frac{1- a^{2} }{1- a^{2} } - \frac{3a ^{2} }{1- a^{2} } )= \frac{2a+1}{a+1} * \frac{(1+a)(1-a)}{(1-2a)(1+2a) } = \frac{1-a}{1-2a}$
2) $( \frac{(2m+1)(2m+1)}{4m^{2} -1} - \frac{(2m-1)(2m-1)}{4m ^{2}-1 } )* \frac{10m-5}{4m} = \frac{(2m+1) ^{2} -(2m-1) ^{2} }{(2m+1)(2m-1)} * \frac{5(2m-1)}{4m} =$ $\frac{4m ^{2}+1+4m-4m ^{2}-1+4m }{2m+1} * \frac{5}{4m} = \frac{4m}{2m+1} * \frac{5}{4m}= \frac{5}{2m+1}$
3)( $\frac{a(x+a)}{(x-a)(x+a)} + \frac{a(x-a)}{(x-a)(x+a)} )* \frac{(x+a) ^{2} }{2 a^{2} } = \frac{a(x+a)+a(x-a)}{(x-a)(x+a)} * \frac{(x+a) ^{2} }{2a ^{2} } = \frac{2ax}{x-a} * \frac{x+a}{2a ^{2} }$ = $\frac{ x^{2} +ax}{ax- a^{2} }$
4) $( \frac{x ^{3} }{xy ^{2} } + \frac{ y^{3} }{xy ^{2} } ):( \frac{ x^{2} }{xy ^{2} } - \frac{xy}{xy ^{2} } + \frac{y ^{2} }{xy ^{2} } )= \frac{x ^{3}+y ^{3} }{xy ^{2} } * \frac{xy ^{2} }{ x^{2} -xy+y ^{2} } = \frac{x ^{3} +x^{3} }{ x^{2} -xy+y ^{2} }$