a) 6x - 3 = 8x + 9
6x = 8x + 9 + 3
6x = 8x + 12
6x - 6x = 8x - 6x + 12
0 = 2x + 12
0 - 12 = 2x
-12 = 2x
2x = -12
x = -12 : 2
x = -6
b) 7x - 5 = 13 - 5x
7x = 13 - 5x + 5
7x = 13 + 5 - 5x
7x = 18 - 5x
7x + 5x = 18 - 5x + 5x
12x = 18 - (5x - 5x)
12x = 18
12x = 18
x = 18 : 12
x = \(\frac{3}{2}\)(hoặc = 1,5)
c) 2 - 3x = 5x + 10
3x = 2 - (5x + 10)
3x = 2 - 5x - 10
3x = 2 - 10 - 5x
3x = -8 - 5x
3x - 3x = -8 - 5x + 3x
0 = -8 - (5x + 3x)
0 = -8 - 8x
-8 - 8x = 0
8x = -8 - 0
8x = -8
x = -8 : 8
x = -1
\(a,6x-3=8x+9\)
\(-3-9=8x-6x\)
\(-12=2x\)
\(-12:2=x\)
\(-6=x\)
Vậy \(x=-6\)
\(b,7x-5=13-5x\)
\(7x+5x=13+5\)
\(12x=18\)
\(x=\frac{18}{12}=\frac{3}{2}\)
\(c,2-3x=5x+10\)
\(-3x-5x=10-2\)
\(-8x=8\)
\(x=8:-8\)
\(x=-1\)
Học tốt !
a) 6x - 3 = 8x + 9
<=> 6x - 8x = 9 + 3
<=> -2x = 12
<=> x = -6
Vậy S = { -6 }
b) 7x - 5 = 13 - 5x
<=> 7x + 5x = 13 + 5
<=> 12x = 18
<=> x = 18/12 = 3/2
Vậy S = { 3/2 }
c) 2 - 3x = 5x + 10
<=> -3x - 5x = 10 - 2
<=> -8x = 8
<=> x = -1
Vậy S = { -1 }
a, \(6x-3=8x+9\Leftrightarrow-2x=12\)
\(\Leftrightarrow x=-\frac{12}{2}=-6\)
b, \(7x-5=13-5x\Leftrightarrow12x-18=0\)
\(\Leftrightarrow12x=18\Leftrightarrow x=\frac{3}{2}\)
c, \(2-3x=5x+10\Leftrightarrow8-8x=0\)
\(\Leftrightarrow x=-1\)
\(6x-3=8x+9\Leftrightarrow-12=2x\Leftrightarrow x=-6\)
\(7x-5=13-5x\Leftrightarrow-18=-12x\Leftrightarrow x=\frac{3}{2}\)
\(2-3x=5x+10\Leftrightarrow-12=8x\Leftrightarrow x=-1\)
