Question

giải phương trình sau

a) \(\dfrac{x+1}{100}+\dfrac{x+2}{99}+\dfrac{x+4}{97}=-4\)

b) \(\dfrac{x-12}{77}+\dfrac{x-11}{78}=\dfrac{x-74}{15}+\dfrac{x-73}{16}\)

Answer 1

a ) \(\dfrac{x+1}{100}+\dfrac{x+2}{99}+\dfrac{x+4}{97}=-4\)

\(\Leftrightarrow\dfrac{x+101}{100}+\dfrac{x+101}{99}+\dfrac{x+101}{97}=-1\)

\(\Leftrightarrow\left(x+101\right)\left(\dfrac{1}{100}+\dfrac{1}{99}+\dfrac{1}{97}\right)=-1\)

Vô lí => Phương trình trên vô nghiệm .

b ) \(\dfrac{x-12}{77}+\dfrac{x-11}{78}=\dfrac{x-74}{15}+\dfrac{x-73}{16}\)

\(\Leftrightarrow\dfrac{x-89}{77}+\dfrac{x-89}{78}-\dfrac{x-89}{15}-\dfrac{x-73}{16}=0\)

\(\Leftrightarrow\left(x-89\right)\left(\dfrac{1}{77}+\dfrac{1}{78}-\dfrac{1}{15}-\dfrac{1}{16}\right)=0\)

\(\Leftrightarrow x=89\)

Vậy x = 89.

Answer 2

Câu a nhằm tí mà chắc đề sai nếu đúng chỉ bk dùng mày tính để tìm nghiệm .

Answer 3

https://i.imgur.com/dFwBQYk.jpg