$a$, ${x}$ + $\frac{2}{5}$ - ${x}$ - $0,5$ = ${x}$ + $\frac{5}{2}$
⇔ $\frac{2}{5}$ - $0,5$ = $x$ + $\frac{5}{2}$
⇔ $\frac{2}{5}$ - $\frac{1}{2}$ = $x$ + $\frac{5}{2}$
⇔ $\frac{-1}{10}$ = $x$ + $\frac{5}{2}$
⇔ $x$ = $\frac{-1}{10}$ - $\frac{5}{2}$
⇔ $x$ = $\frac{-13}{5}$
$b$, $\frac{3x}{x-1}$ - $\frac{2x}{1+x}$ = $\frac{x^2+5}{x^2-1}$ $ĐK$: $x$ $\neq$ ±$1$
⇔ $\frac{3x}{x-1}$ - $\frac{2x}{1+x}$ = $\frac{x^2+5}{(x-1)(x+1)}$
⇔ $\frac{3x(x+1)-2x(x-1)-x^2-5}{(x-1)(x+1)}$ = $0$
⇔ $3x^{2}$ + $3x$ - $2x^2$ + $2x$ - $x^2$ - $5$ = $0$
⇔ $5x-5$ = $0$ <=> $x$ = $1$ $(l)$
⇔ $pt$ $vô$ $nghiệm$
$c$, bạn viết rõ đề ra nhé!
CHÚC BẠN HỌC TỐT!
