[(15+75:x)*13+500]:20=38.
(15+75:x)*13+500=38×20
(15+75:x)*13=760-500
(15+75:x)*13=260
15+75:x=260:13
75:x=20-15
75:x=5
x=15
2*{27-2*[3*x-(35:5-2*3)]+3}:4 =10
27-2*[3*x-(7-6)]+3 =10 *4 :2
30-2*(3*x-1) =20
-2*(3*x-1) =20-30
-2*(3*x-1) =-10
2*(3*x-1) =10
3*x-1 =10:2
3*x-1 =5
3*x =6
x=2