求未知数x5x=4x+8
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求未知数x
5x=4x+8
7x-6=2x+4
2x+5=25-8x
7x-3=6x.
5x=4x+8
7x-6=2x+4
2x+5=25-8x
7x-3=6x.
(1)5x=4x+8
5x-4x=4x+8-4x
x=8;
(2)7x-6=2x+4
7x-6-2x=2x+4-2x
5x-6=4
5x-6+6=4+6
5x=10
5x÷5=10÷5
x=2;
(3)2x+5=25-8x
2x+5+8x=25-8x+8x
10x+5=25
10x+5-5=25-5
10x=20
10x÷10=20÷10
x=2;
(4)7x-3=6x
7x-3-6x=6x-6x
x-3=0
x-3+3=0+3
x=3.
5x-4x=4x+8-4x
x=8;
(2)7x-6=2x+4
7x-6-2x=2x+4-2x
5x-6=4
5x-6+6=4+6
5x=10
5x÷5=10÷5
x=2;
(3)2x+5=25-8x
2x+5+8x=25-8x+8x
10x+5=25
10x+5-5=25-5
10x=20
10x÷10=20÷10
x=2;
(4)7x-3=6x
7x-3-6x=6x-6x
x-3=0
x-3+3=0+3
x=3.