1) 2x - 378 = 122
=> 2x = 122 + 378
=> 2x = 500
=> x = 500 : 2
=> x = 250
2) 8x - 4x = 1208
=> 4x = 1208
=> x = 1208 : 4
=> x = 302
3) x - 382 = 159 : 3
=> x - 382 = 53
=> x = 53 + 382
=> x = 435
4) 3x + 30 = 420
=> 3x = 420 - 30
=> 3x = 390
=> x = 390 : 3
=> x = 130
5) 12x - 13x - 500 = 1500
=> -x = 1500 + 500
=> -x = 2000
=> x = -2000
1,\(2x-378=122\)
\(2x=122+378\)
\(2x=500\)
\(x=500:2\)
\(x=250\)
2,\(8x-4x=1208\)
\(x.\left(8-4\right)=1208\)
\(x.4=1208\)
\(x=1208:4\)
\(x=302\)
3,\(x-382=159:3\)
\(x-382=53\)
\(x=52+382\)
\(x=434\)
4,\(3x+30=420\)
\(3x=420-30\)
\(3x=390\)
\(x=390:3\)
\(x=130\)
5,\(12x-13x-500=1500\)
như câu 2
\(1,2x-378=122\)\(\Rightarrow2x=500\Rightarrow x=250\)
\(2,8x-4x=1208\)\(\Rightarrow4x=1208\Rightarrow x=302\)
\(3,x-382=159\div3\)\(\Rightarrow x-382=53\Rightarrow x=435\)
\(4,3x+30=402\)\(\Rightarrow3x=372\Rightarrow x=124\)
\(5,12x-13x-500=1500\)\(\Rightarrow-x-500=1500\Rightarrow-x=1000\Leftrightarrow x=-1000\)
Cảm ơn tất cả các bạn đã giải bài này!!!!!
1) 2x - 378 = 122
2x = 122 + 378
2x = 500
x = 500 : 2
x = 250
2) 8x - 4x = 1208
4x = 1208
x = 1208 : 4
x = 302
3) x- 382 = 159 : 3
x - 382 = 53
x = 53 + 382
x = 435
4) 3x + 30 = 420
3x = 420 - 30
3x = 390
x = 390 : 3
x = 130
5) 12x - 13x - 500 = 1500
12x - 13x = 1500 + 500
12x - 13x = 2000
-1x = 2000
x = 2000 : (-1)
x = -2000
