Question

0,3(0,4х-1,2)+0,36x=3

Answer 1

0,12х-0,36+0,36х=3

0,48х=3,36

х=7

Answer 2

$0.3(0.4x - 1.2) + 0.36x = 3 \\ 0.12x - 0.36 + 0.36x = 3 \\ 0.48x = 3.36 \\ x = 3.36 \div 0.48 = 7$