a)x-$\frac{3}{10}$=$\frac{7}{15}$:$\frac{3}{5}$
b)$\frac{8}{23}$.$\frac{46}{24}$=$\frac{1}{3}$x
c)x:(-1$\frac{3}{21}$)+3$\frac{1}{2}$=-1$\frac{3}{4}$
d)x-25%.x=0,5
a)x-$\frac{3}{10}$=$\frac{7}{15}$:$\frac{3}{5}$
b)$\frac{8}{23}$.$\frac{46}{24}$=$\frac{1}{3}$x
c)x:(-1$\frac{3}{21}$)+3$\frac{1}{2}$=-1$\frac{3}{4}$
d)x-25%.x=0,5
`a)x-3/10=7/15:3/5`
`=>x-3/10=7/15.(5)/3`
`=>x-3/10=7/9`
`=>x=7/9+3/10`
`=>x=97/90`
vậy `x=97/90`
`b)8/23.(46)/24=1/3x`
`=>2/3=x/3`
`=>x=2`
vậy `x=2`
`c)x:(-1cc3/21)+3cc1/2=-1cc3/4`
`=>x:(-8)/7+7/2=-7/4`
`=>(-7x)/8=-7/4-7/2`
`=>(-7x)/8=-21/4`
`=>-28x=-168`
`=>x=6`
`d)x-25%.x=0,5`
`=>x-1/4.x=0.5`
`=>x-x/4=0,5`
`=>4x-x=2`
`=>3x=2`
`=>x=2/3`
Đáp án-Giải thích các bước giải:
a)`x-3/10=7/15:3/5`
`<=>x-3/10=7/15 . 5/3`
`<=>x-3/10=7/9`
`<=>x=7/9+3/10`
`<=>x=97/90`
Vậy `x=97/90`
b) `8/23 . 46/24 =1/3 x`
`<=>2/3=1/3 x`
`<=>x=2/3:1/3`
`<=>x=2/3 .3`
`<=>x=2`
Vậy `x=2`
c)`x:(-1 3/21)+3 1/2=-1 3/4`
`<=>x:(-8/7)+7/2=-7/4`
`<=>x:(-8/7)=-7/4-7/2`
`<=>x:(-8/7)=-21/4`
`<=>x=-21/4. (-8/7)`
`<=>x=6`
Vậy `x=6`
d)`x-25%.x=0,5`
`<=>x.(1-25%)=0,5`
`<=>x.(1-0,25)=0,5`
`<=>x.0,75=0,5`
`<=>x.3/4=1/2`
`<=>x=1/2:3/4`
`<=>x=2/3`
Vậy `x=2/3`