=>-2x+1-3/2+5=7
=>-2x+4,5=7
=>-2x=2,5
=>x=-1,25
\(-2\left(x-\dfrac{1}{2}\right)-5.\left(-\dfrac{7}{10}\right)=7\\ -2x+1+\dfrac{7}{2}=7\\ -2x+\dfrac{9}{2}=7\\ -2x=7-\dfrac{9}{2}\\ -2x=\dfrac{5}{2}\\ x=\dfrac{5}{2}:\left(-2\right)\\ x=-\dfrac{5}{4}\)
`-2(x-1/2) - 5(3/10 -1) =7`
`<=> -2x + 1 - 15/10 + 5 =7`
`<=> -2x + 9/2 =7`
`=> -2x = 7 -9/2 =14/2 -9/2`
` -2x = 5/2`
`=> x = 5/2 : (-2) = 5/(-2*2) = -5/4`
Vậy `x=-5/4`
`-2(x-1/2)-5(3/10-1)=7`
`=>-2(x-1/2)-5 .(-7/10)=7`
`=>-2(x-1/2)-(-7/2)=7`
`=>-2(x-1/2)+7/2=7`
`=> -2(x-1/2)=7-7/2`
`=> -2(x-1/2)=7/2`
`=>x-1/2 = 7/2 . (-1/2)`
`=>x-1/2=-7/4`
`=>x=-7/4+1/2`
`=>x= -5/4`