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(1)96-5x=42 96-5x+5x=42+5x5x+42=965x+42-42=96-4

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(1)96-5x=42 96-5x+5x=42+5x5x+42=965x+42-42=96-4
(1)96-5x=42
96-5x+5x=42+5x
5x+42=96
5x+42-42=96-42
5x=54
5x÷5=54÷5
x=10.8;

(2)8x+0.4×1.2=2.4
8x+0.48=2.4
8x+0.48-0.48=2.4-0.48
8x=1.92
8x÷8=1.92÷8
x=0.24;

(3)7.2-5x=3.6
7.2-5x+5x=3.6+5x
5x+3.6=7.2
5x+3.6-3.6=7.2-3.6
5x=3.6
5x÷5=3.6÷5
x=0.72;

(4)9x÷3=5.4
9x÷3×3=5.4×3
9x=16.2
9x÷9=16.2÷9
x=1.8;

(5)2.9x+1.28=7.08
2.9x+1.28-1.28=7.08-1.28
2.9x=5.8
2.9x÷2.9=5.8÷2.9
x=2;

(6)4x-19.5=4.1
4x-19.5+19.5=4.1+19.5
4x=23.6
4x÷4=23.6÷4
x=5.9.