tìm x
a 3 ( x – 4 ) – 25 ( x + 5 ) = -16 -x
b – 5 ( 6 – 2x ) + 5 ( 15 – 3x ) = 2x + 5
c 4 ( 5 – 3x ) – 2 ( 15 x -10 ) = 4x – 2
d -5 ( 4x + 2 ) + 10 ( 3x – 4 ) = 15x -5
e 2 ( 3 -4x ) – 6 ( 5 -2x ) = 30x + 6
ai làm nhanh giúp mik nha
gấp lắm ai xong trước mik cho ctlhn
`a)` `3(x-4)-25(x+5)=-16-x`
`=>3x-12-25x-125=-16-x`
`=>-22x-137=-16-x`
`=>-22x+x=-16+137`
`=>-21x=121`
`=>x=-121/21`
Vậy `x=-121/21`
`b)` `-5(6-2x)+5(15-3x)=2x+5`
`=>-30+10x+75-15x=2x+5`
`=>-5x+45=2x+5`
`=>-5x-2x=5-45`
`=>-7x=-40`
`=>x=40/7`
Vậy `x=40/7`
`c)` `4(5-3x)-2(15x-10)=4x-2`
`=>20-12x-30x+20=4x-2`
`=>-42x+40=4x-2`
`=>-42x-4x=-2-40`
`=>-46x=-42`
`=>x=21/23`
Vậy `x=21/23`
`d)` `-5(4x+2)+10(3x-4)=15x-5`
`=>-20x-10+30x-40=15x-5`
`=>10x-50=15x-5`
`=>10x-15x=-5+50`
`=>-5x=45`
`=>x=-9`
Vậy `x=-9`
`e)` `2(3-4x)-6(5-2x)=30x+6`
`=>6-8x-30+12x=30x+6`
`=>4x-24=30x+6`
`=>4x-30x=6+24`
`=>-26x=30`
`=>x=-15/13`
Vậy `x=-15/13`
Đáp án + Giải thích các bước giải:
`a)`
`3(x-4)-25(x+5)=-16-x`
`=>3x-12-25x-125=-16-x`
`=>3x-25x+x=-16+125+12`
`=>-21x=121`
`=>x=121/(-21)=-121/21`
Vậy `x=-121/21`
`b)`
`-5(6-2x)+5(15-3x)=2x+5`
`=>-30+10x+75-15x=2x+5`
`=>10x-15x-2x=5-75+30`
`=>-7x=-40`
`=>x=(-40)/(-7)=40/7`
Vậy `x=40/7`
`c)`
`4(5-3x)-2(15x-10)=4x-2`
`=>20-12x-30x+20=4x-2`
`=>-12x-30x-4x=-2-20-20`
`=>-46x=-42`
`=>x=42/46=21/23`
Vậy `x=21/23`
`d)`
`-5(4x+2)+10(3x-4)=15x-5`
`=>-20x-10+30x-40=15x-5`
`=>-20x+30x-15x=-5+40+10`
`=>-5x=45`
`=>x=45-:(-5)=-9`
Vậy `x=-9`
`e)`
`2(3-4x)-6(5-2x)=30x+6`
`=>6-8x-30+12x=30x+6`
`=>-8x+12x-30x=6+30-6`
`=>-26x=30`
`=>x=30/(-26)=-15/13`
Vậy `x=-15/13`