Đáp án:
$\text{ $\dfrac{x+43}{57}$ + $\dfrac{x+46}{54}$ + $\dfrac{x+49}{51}$ + $\dfrac{x+235}{45}$ = 0}$
$\text{⇔ $\dfrac{x+43}{57}$ +1 + $\dfrac{x+46}{54}$ + 1 + $\dfrac{x+49}{51}$+1 + $\dfrac{x+235}{45}$ -3=0}$
$\text{⇔ $\dfrac{x+100}{57}$ + $\dfrac{x+100}{54}$ + $\dfrac{x+100}{51}$+ $\dfrac{x+100}{45}$ =0}$
$\text{⇔ (x+100)( $\dfrac{1}{57}$ + $\dfrac{1}{54}$ + $\dfrac{1}{51}$ + $\dfrac{1}{45}$) =0 }$
$\text{⇔ $\dfrac{1}{57}$ + $\dfrac{1}{54}$ + $\dfrac{1}{51}$ + $\dfrac{1}{45}$ > 0 (loại) }$
$\text{⇔ x + 100 =0 }$
$\text{⇔ x = -100}$
$\text{Vậy phương trình có tập nghiệm S={ -100} }$
