解方程6x+4×(10-x)=484x+48=7x-15(60+70)x=(50+70)×(x+2)(x+20)×2=2
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(1)6x+4×(10-x)=48,

6x+40-4x=48,

2x+40-40=48-40,

2x=8,

2x÷2=8÷2,

x=4;

(2)4x+48=7x-15,

4x+48+15=7x-15+15,

4x+63-4x=7x-4x,

63=3x,

63÷3=3x÷3,

x=21;

(3)(60+70)x=(50+70)×(x+2),

130x=120x+240,

130x-120x=120x+240-120x,

10x=240,

10x÷10=240÷10,

x=24;

(4)(x+20)×2=2.5x+20,

2x+40=2.5x+20,

2x+40-2x=2.5x+20-2x,

40-20=20+0.5x-20,

20=0.5x,

20÷0.5=0.5x÷0.5,

x=40;

(5)x-10=[2×(x-10)-9]×5,

x-10=[2x-20-9]×5,

x-10=10x-145,

x-10+145=10x-145+145,

x+135-x=10x-x,

135=9x,

135÷9=9x÷9,

x=15;

(6)3200x+6000×(6-x)=26200,

3200x+36000-6000x=26200,

36000-2800x=26200,

36000-2800x+2800x=26200+2800x,

36000-26200=26200+2800x-26200,

9800=2800x,

9800÷2800=2800x÷2800,

x=3.5.

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