(1)2.6+3.4x=23
3.4x=23-2.6
x=6 (2)12.3÷x=8.2
x=12.3÷8.2
x=1.5
(3)2x-12+3=26
2x=35
x=17.5 (4)21.3x-18.8x=1
2.5x=1
x=0.4