$5)A5$=$\frac{2x^2-12x}{x-6}$ - $\frac{1-x^2}{x+1}$ +`3-2x`
$A5$=$\frac{2x(x-6)}{x-6}$ -$\frac{(1-x)(1+x)}{x+1}$ +`3-2x`
$A5=2x-1+x+3-2x$
$A5=x+2$
Vậy $A5=x+2$
$6)A6$=$\frac{x+1}{2x-2}$ +$\frac{x^2+3}{2-2x^2}$
$A6$=$\frac{x+1}{2(x-1)}$ +$\frac{x^2+3}{2(1-x^2)}$
$A6$=$\frac{x+1}{2(x-1)}$ -$\frac{x^2+3}{2(x^2-1)}$
$A6$=$\frac{(x+1)^2-x^2-3}{2(x-1)(x+1)}$
$A6$=$\frac{x^2+2x+1-x^2-3}{2(x-1)(x+1)}$
$A6$=$\frac{2(x-1)}{2(x-1)(x+1)}$
$A6$=$\frac{1}{x+1}$
Vậy $A6$=$\frac{1}{x+1}$
$7)A7$=$\frac{6}{x-5}$ -$\frac{6-2x}{25-x^2}$ +$\frac{4}{x+5}$
$A7$=$\frac{6}{x-5}$ +$\frac{6-2x}{x^2-25}$ +$\frac{4}{x+5}$
$A7$=$\frac{6(x+5)}{(x-5)(x+5)}$+ $\frac{6-2x}{(x-5)(x+5)}$ +$\frac{4(x-5)}{(x-5)(x+5)}$
$A7$=$\frac{6x+30+6-2x+4x-20}{(x-5)(x+5)}$ =$\frac{8x+16}{(x-5)(x+5)}$
Vậy $A7$=$\frac{8x+16}{(x-5)(x+5)}$
chúc bn học tốt
Mk xin trả lời hay nhất nhé bn♡
