math 2 7
c
1
C
2
a
b
a
b
c
1
2
3
4
x
y
3
7
a
b
a
a
b
x
x
x
3
0
x
0
x
V
F
U
x
0
a
U
F
U
5
x
0
1
x
2
0
1
x
x
C
x
C
f
x
0
1
x
2
x
t
0
t
t
1
t
x
2
x
y
t
u
0
t
t
1
0
u
u
1
t
u
x
2
y
3
0
1
f
0
1
f
x
2
f
x
2
x
y
x
4
f
i
0
100
x
i
x
x
9
x
x
9
x
10