6x÷2＋（x＋4）×4÷2＝（6＋4）×4÷2
6x+(x+4)*4=40
6x+4x+16=40
10x=40-16
10x=24
x=2.4
（3－10/7﹚÷1/2×2/5
=(3-10/7)*2*2/5
=(3-10/1*4/5
=3*4/5-10/7*4/5
=12/5-8/7
=84/35-40/35
=44/35
=1又35分之9