Tìm x
1/ 5.(4-x)-7.(-x+2)=4-9=3
2/ -3.(x-5)+6.(x+2)=9
3/ 4.x-5.(-3+x)=7
4/ 5.(x-3)-2.(x+6)=9
5/ 5.(x-7)+10.(3-x)=20
6/ -4.(x+1)+8.(x-3=24
7/ 7.(5-x) +5.(x-2)=15
8/ 4.(x-1)-3.(x-2)=-/-5/
No Spam :>
Tìm x
1/ 5.(4-x)-7.(-x+2)=4-9=3
2/ -3.(x-5)+6.(x+2)=9
3/ 4.x-5.(-3+x)=7
4/ 5.(x-3)-2.(x+6)=9
5/ 5.(x-7)+10.(3-x)=20
6/ -4.(x+1)+8.(x-3=24
7/ 7.(5-x) +5.(x-2)=15
8/ 4.(x-1)-3.(x-2)=-/-5/
No Spam :>
Đáp án:
`↓↓`
Giải thích các bước giải:
`1) 5(4-x)-7(-x+2)=4-9+3`
`=> 20-5x+7x-14=-2`
`=> 2x=-2+14-20`
`=> 2x=-8`
`=> x=-4`
`2) -3(x-5)+6(x+2)=9`
`=> -3x+15+6x+12=9`
`=> 3x=9-12-15`
`=> 3x=-18`
`=> x=-6`
`3) 4x-5(-3+x)=7`
`=> 4x+15-5x=7`
`=> -x=7-15`
`=> -x=-8`
`=> x=8`
`4) 5(x-3)-2(x+6)=9`
`=> 5x-15-2x-12=9`
`=> 3x=9+12+15`
`=> 3x=36`
`=> x=12`
`5) 5(x-7)+10(3-x)=20`
`=> 5x-35+30-10x=20`
`=> -5x=20-30+35`
`=> -5x=25`
`=> x=-5`
`6) -4(x+1)+8(x-3)=24`
`=> -4x-4+8x-24=24`
`=> 4x=24+24+4`
`=> 4x=52`
`=> x=13`
`7) 7(5-x)+5(x-2)=15`
`=> 35-7x+5x-10=15`
`=> -2x=10+15-35`
`=> -2x=-10`
`=> x=5`
`8) 4(x-1)-3(x-2)=-|-5|`
`=> 4x-4-3x+6=-5`
`=> x=-5-6+4`
`=> x=-7`
Đáp án:
1) 5.(4 – x) – 7.(-x + 2) = 4 – 9 + 3
\(\Leftrightarrow 20 – 5x + 7x – 14 =-2 \)
\(\Leftrightarrow 2x=-8\)
\(\Leftrightarrow x=-4\)
2) -3.(x – 5) + 6.(x + 2) = 9
\(\Leftrightarrow -3x + 15 + 6x + 12 = 9\)
\(\Leftrightarrow 3x = -18\)
\(\Leftrightarrow x=-6\)
3) 4.x – 5.(-3 + x) = 7
\(\Leftrightarrow 4x + 15 – 5x = 7\)
\(\Leftrightarrow -x = -8\)
\(\Leftrightarrow x=8\)
4) 5.(x – 3) – 2.(x + 6) = 9
\(\Leftrightarrow 5x-15-2x-12=9\)
\(\Leftrightarrow 3x = 36\)
\(\Leftrightarrow x=12\)
5) 5.(x – 7) + 10.(3 – x) = 20
\(\Leftrightarrow 5x – 35 + 30 – 10x = 20\)
\(\Leftrightarrow -5x = 25\)
\(\Leftrightarrow x = -5\)
6) -4.(x + 1) + 8.(x – 3) = 24
\(\Leftrightarrow -4x – 4 + 8x – 24 = 24\)
\(\Leftrightarrow 4x = 52\)
\(\Leftrightarrow x = 13\)
7) 7.(5 – x) + 5.(x – 2) = 15
\(\Leftrightarrow 35-7x+5x-10=15\)
\(\Leftrightarrow -2x = 15 – 25\)
\(\Leftrightarrow -2x = -10\)
\(\Leftrightarrow x=5\)
8) 4.(x – 1) – 3.(x – 2) = -|-5|
\(\Leftrightarrow 4x – 4 – 3x + 6 = -5\)
\(\Leftrightarrow x = -5-2\)
\(\Leftrightarrow x=-7\)