X÷0.7+1.2×3=4.1
x÷0.7=4.1-3.6
x÷0.7=0.5
x=0.5x0.7
x=0.35

（X+4.6）÷1.2=7.8
x+4.6=7.8x1.2
x=9.36-4.6
x=4.76