1) X² - 3XY = X * ( X - 3Y )
2) X² / ( X * ( X - 3Y )) = X / ( X - 3Y )
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3) X^2 - 9Y^2 = ( X - 3Y )*( X + 3Y )
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[ X / ( X - 3Y ) ] * [ (( X - 3Y )*( X + 3Y ) ) / X ] = X + 3Y
ОТВЕТ Х + 3Y
5) -4; 4. 0; -2/3
6) -4; 4.-7; 7
9y=(2sinx+3)/√x
u=2sinx+3 u'=2cosx
v=√x v'=1/2√x
(u/v)'=1/v²[u'v-v'u]=1/x[2√x*cosx-(2sinx+3)/2√x]