Đáp án:
Giải thích các bước giải:
$\frac{109-x}{91}$ + $\frac{107-x}{93}$ + $\frac{105-x}{95}$ +$\frac{103-x}{97}$ +4 =0
(=) $\frac{109-x}{91}$ + $\frac{107-x}{93}$ + $\frac{105-x}{95}$ +$\frac{103-x}{97}$ =-4
(=) $\frac{109-x}{91}$ +1+ $\frac{107-x}{93}$ +1 + $\frac{105-x}{95}$+1 +$\frac{103-x}{97}$+1=0
(=) $\frac{109-x+91}{91}$+ $\frac{107-x+93}{93}$+ $\frac{105-x+95}{95}$ +$\frac{103-x+97}{97}$ =0
(=) $\frac{200-x}{91}$ + $\frac{200-x}{93}$ + $\frac{200-x}{95}$ +$\frac{200-x}{97}$ =0
(=) (200 - x ) ( $\frac{1}{91}$ + $\frac{1}{93}$ + $\frac{1}{95}$ +$\frac{1}{97}$ ) =0
(=) 200-x =0
(=) x = 200