Đáp án:
`x=1`
Giải thích các bước giải:
`(-7x)/1.9+(-7x)/9.17+(7x)/(-17.25)+(7x)/(-25.33)=(-28)/33`
`=>(-7x)/1.9+(-7x)/9.17+(-7x)/17.25+(-7)/25.33=(-28)/33`
`=>(7x)/1.9+(7x)/9.17+(7x)/17.25+(7x)/25.33=(28)/33`
`=>\underbrace{(7x)/1.9+(7x)/9.17+(7x)/17.25+(7x)/25.33}_{A}=(28)/33`
`=>A=(7x)/1.9+(7x)/9.17+(7x)/17.25+(7x)/25.33`
`=>A/7=x/1.9+x/9.17+x/17.25+x/25.33`
`=>`$\dfrac{\dfrac{A}{7}}{x}$`=1/1.9+1/9.17+1/17.25+1/25.33=28/33`
`=>`$\dfrac{\dfrac{8A}{7}}{x}$`=8/1.9+8/9.17+8/17.25+8/25.33=28/33`
`=>`$\dfrac{\dfrac{8A}{7}}{x}$`=1-1/9+1/9-1/17+1/17-1/25+1/25-1/33=28/33`
`=>`$\dfrac{\dfrac{8A}{7}}{x}$`=1-1/33=28/33`
`=>`$\dfrac{\dfrac{8A}{7}}{x}$`=32/33`
`=>`$\dfrac{8A}{7}$`=32/33*x`
`=>8A=(7.32x)/33`
`=>A=(7.32x)/33÷8`
`=>A=(7.32x÷8)/33`
`=>A=(7.4x)/33`
`=>A=(28x)/33`
`=>(28x)/33=28/33`
`=>28x=28`
`=>x=28÷28`
`=>x=1`
Vậy `x=1`.
