Question

[Nguyễn Thanh Thảo]

giải pt

\(\dfrac{x-3}{11}+\dfrac{x+1}{3}=\dfrac{x+7}{9}-1\)

Answer 1

[Trần Quân]

<=>\(\dfrac{\left(x-3\right)9}{99}+\dfrac{\left(x+1\right)33}{99}=\dfrac{\left(x+7\right)11}{99}-\dfrac{99}{99}\)

=>(x-3)9 + (x+1)33 = (x+7)11 - 99

=>9x-27+33x+33=11x+77-99

=>9x+33x-11x=27-33+77-99

=>31x=-28

=>x=\(\dfrac{-28}{31}\)

Answer 2

[lê thị hương giang]

\(\dfrac{x-3}{11}+\dfrac{x+1}{3}=\dfrac{x+7}{9}-1\)

\(\Leftrightarrow\dfrac{9\left(x-3\right)+33\left(x+1\right)}{99}=\dfrac{11\left(x+7\right)-99}{99}\)

\(\Leftrightarrow9\left(x-3\right)+33\left(x+1\right)=11\left(x+7\right)-99\)

\(\Leftrightarrow9x-27+33x+33=11x+77-99\)

\(\Leftrightarrow9x+33x-11x=77-99+27-33\)

\(\Leftrightarrow31x=-28\)

\(\Leftrightarrow x=-\dfrac{28}{31}\)

Vậy phương trình có nghiệm duy nhất \(x=-\dfrac{28}{31}\)