a) k=7n; n
k=7n |:7
n = k/7
b) a= k+6; k
a= k+6 | - 6
k = a - 6
c) z= 7-y; y
z= 7-y |+ y
z + y = 7 | - z
y = 7 - z
d) d= a +bc; c
d = a + bc | - a
d - a = bc|:b
c = d - a / b
e) x= 2k + 1; k
x - 1 = 2k |:2
k = x - 1/2
f) 2k= 7n+ 5; n
2 k - 5 = 7n |:7
n = 2k - 5/7
