Question

350(в), 351(г), 372(б) плиииз... срочно

Answer 1

$350. \B) frac{2}{3-a} + frac{a^2-4}{a^2-9} * frac{a+3}{a-2} = frac{2}{3-a}+ frac{(a+2)(a-2)(a+3)}{(a-3)(a+3)(a-2)} = frac{2}{3-a}+ frac{a+2}{a-3}=\= frac{2}{3-a}- frac{a+2}{3-a}= frac{-a}{3-a} = frac{a}{a-3}$$351.\b) (y- frac{y^2}{y+1} ): ( y- frac{y}{y+1} )=( frac{y^2+y-y^2}{y+1} ):( frac{y^2+y-y}{y+1} ) = frac{y(y+1)}{(y+1)y^2} = frac{1}{y}$
$352.\b) frac{1}{y+3}+ frac{2}{y^2+4y+3} =frac{1}{y+3}+ frac{2}{(y+1)(y+3)} = frac{y+1+2}{(y+1)(y+3)}= frac{y+3}{(y+1)(y+3)}= frac{1}{y+1} \y^2+4y+3=(y+1)(y+3)\y^2+4y+3=0\D=b^2-4ac=16- 12=4=2^2,D textgreater 0\y_{1,2}= frac{-bб sqrt{D} }{2a} = frac{-4б2}{2} =|{ {{y=-1} atop {y=-3}} right.$
Ответ: $frac{1}{y+1}$