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a) 3x – 10 = 2x + 13
b) x + 12 = -5 – x
c) x + 5 = 10 – x
d) 6x + 23 = 2x – 12
e) 12 – x = x + 1
f) 14 + 4x = 3x + 20
g) 2.(x-1) + 3(x-2) = x -4
h) 3.(4 – x) – 2.(x- 1) = x + 20
i) 4.(2x + 7) – 3. (3x – 2) = 24
k) 3(x – 2) + 2x = 10
Đáp án:
a, `3x – 10 =2x +13`
`3x – 2x =13 +10`
`x =23`
b, ` x + 12 =-5 -x`
`x + x =-5 -12`
`2x =-17`
`x =-17/2`
c, ` x+ 5= 10 -x`
`x + x =10 – 5`
`2x =5`
`x =5/2`
d, `6x + 23 =2x – 12`
`6x – 2x =-12 – 23`
`4x =-35`
`x =-35/4`
e,`12 -x = x +1`
`-x – x =1 -12`
`-2x =-11`
` x =-11 : -2=11/2`
f, `14 + 4x = 3x + 20`
`4x – 3x =20 -14`
`x =6`
g,`2.(x-1) + 3.(x-2)=x-4`
`2x – 2 + 3x – 6 =x – 4`
`2x + 3x -x =-4 + 2 +6`
`4x =4`
`x =4 : 4=1`
h, `3.(4-x) – 2.(x-1) =x+20`
`12 – 3x -2x + 2 =x+20`
`-3x -2x -x =20 – 2 -12`
`-6x =6`
`x =6 : (-6)=-1`
i, `4.(2x+7) – 3.(3x-2)=24`
`8x + 28 – 9x + 6 =24`
`8x – 9x =24 – 6 -28`
`-x =-10`
`⇒ x=10`
k, `3.(x-2) + 2x = 10`
` 3x – 6 + 2x =10`
` 3x + 2x =10 +6`
` 5x =16`
` x =16/5`
`text{ XIN HAY NHẤT NHA}`
@toanisthebest
`3x – 10 = 2x + 13`
`=> 3x – 2x = 10 + 13`
`=> x = 23`
—
`x + 12 = -5 – x`
`=> x + x = -12 – 5`
`=>2x = -17`
`=> xx + 5 = 10 – x = (-17)/2`
—
`x + 5 = 10 – x`
`=> x + x = 10 – 5`
`=> 2x = 5`
`=> x = 5/2`
—
`6x + 23 = 2x – 12`
`=> 6x – 2x = -23 – 12`
`=> 4x = -35`
`=> x = (-35)/4`
—
`12 – x = x + 1`
`=> 12 – 1 = x + x`
`=> 11 = 2x`
`=> x = 11/2`
—
`14 + 4x = 30x + 20`
`=> 4x – 30x = -14 + 20`
`=> -26x = 6`
`=> x = 6/-26`
`=> x = (-3)/13`
—
`2. (x – 1) + 3 . (x – 2) = x – 4`
`=> 2x – 2 + 3x – 6 = x – 4`
`=> 5x – 8 = x – 4`
`=> 5x – x = 8 – 4`
`=> 4x = 2`
`=> x = 1/2`
—
`3 . (4 – x) – 2. (x – 1) = x + 20`
`=> 12 – 3x – 2x + 2 = x + 20`
`=> 14 – 5x = x + 20`
`=> -5x – x = 14 + 20`
`=> -6x = 34`
`=> x = (-17)/3`
—
`4 . (2x + 7) – 3 . (3x – 2) = 24`
`=> 8x + 28 – 9x + 6 = 24`
`=> -x + 34 = 24`
`=> -x = 24 – 34`
`=> -x = -10`
`=> x = 10`
—
`3 . (x – 2) + 2x = 10`
`=> 3x – 6 + 2x = 10`
`=> 5x – 6 = 10`
`=> 5x = 10 + 6`
`=> 5x = 16`
`=> x = 16/5`