a) $\frac{x+2}{93}$+1+ $\frac{x+3}{92}$+1 = $\frac{x+4}{91}$+1+ $\frac{x+5}{90}$ +1
⇔ $\frac{x+95}{93}$ + $\frac{x+95}{92}$- $\frac{x+95}{91}$-$\frac{x+95}{90}$=0
⇔(x+95)$(\frac{1}{93}+$$\frac{1}{92}-$$\frac{1}{91}-$$\frac{1}{90})=0$
Vì $\frac{1}{93}+$$\frac{1}{92}+$$\frac{1}{91}+$$\frac{1}{90}\neq0$
pt ⇔ x+95=0 ⇔ x=-95
b) Tương tự câu a)
$\frac{x+98}{48}$-1+ $\frac{x+80}{30}$-1 + $\frac{25}{25}$+1+ $\frac{x+10}{40}$ +1=0
⇔ x+50 =0
⇔ x=-50
