Question

Efectuati
a pe a-b - b pe a+b=
3x+2 pe x la patrat +2x +1 -4 pe x+1=
dau coroana si 100 p

Answer 1

$\frac{a}{a-b} - \frac{b}{a+b} = \frac{a(a+b)-b(a-b)}{a ^{2} -b ^{2} } = \frac{a ^{2} +ab-ab+b ^{2} }{a ^{2} -b ^{2} } = \frac{a ^{2} +b ^{2} }{a ^{2} -b ^{2} }$

$\frac{3x+2}{ x^{2} +2x+1} - \frac{4}{x+1} = \frac{3x+2-4(x+1)}{(x+1) ^{2} } = \frac{3x+2-4x-4}{(x+1) ^{2} } = \frac{-x-2}{(x+1) ^{2} } =- \frac{x+2}{(x+1) ^{2} }$