Bài 1
415- 2*(x -19)-15=20
<=> 415 - 2x + 38 - 15 = 20
<=> 438 -2x = 20
<=> 2x = 418
<=> x = 209
5*x-14+x=100+4*x
<=> 6x- 14 = 100 + 4x
<=> 2x = 114
<=> x = 57
415-2(x-19)-15=20
415-2x+38-15=20
(415+38-15)-2x=20
438-2x=20
2x=438-20
2x=418
x=418:2
x=204
5x-14+x=100+4x
5x+x-4x=100+14
2x=114
x=114:2
x=57
\(415-2.\left(x-19\right)-15=20\)
\(\Leftrightarrow400-2.\left(x-19\right)=20\)
\(\Leftrightarrow2.\left(x-19\right)=380\)
\(\Leftrightarrow x-19=190\)
\(\Leftrightarrow x=209\)
\(5x-14+x=100+4x\)
\(\Leftrightarrow6x-14=100+4x\)
\(\Leftrightarrow6x-4x=100+14\)
\(\Leftrightarrow2x=114\)
\(\Leftrightarrow x=57\)
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