Solution:

45-6 = 78 / 2 = 39 * 1

Explanation:
A = 4
B = 5
C = 6
D = 7
E = 8
F = 2
G = 3
H = 9
I = 1

So below equation can be solved as:
AB - C = DE / F = GH * I
45 - 6 = 78/2 = 39 * 1
39 = 39 = 39.

Solution:

There can be two possible solutions as shown in the picture below.

1,19,3,12,16,14,18,10,7,6,15,2,5,9,13,17,8,11,4
1,19,3,18,16,14,12,4,13,6,9,8,17,15,7,5,2,11,10

Solution:

457730 * 4 = 1830920
(DOLLAR * 4 = QUARTER)

Solution:

26

Explanation:
14 = 1^2 + 2^2 + 3^2
21 = 4^2 + 1^2 + 2^2
29 = 4^2 + 3^2 + 2^2
26 = 3^2 + 4^2 + 1^2

Solution:

3 + 3 = 8 can be set true by moved to one of two solution.
A) 5 + 3 = 8
B) 3 + 5 = 8

Solution:

Horse = 10
Cowboy-Boot = 1
HorseShoe= 2
The Last equation = 21

Detailed Explanation :
Equation1:
3Horse = 30
=> Horse = 10 .....(1)

Equation2:
1Horse + 2HorseShoe + 2HorseShoe = 18
10 + 4HorseShoe =18
HorseShoe = 2 .....(3)

Equation3:
2HorseShoe - 2Cowboy-Boot = 2
4 - 2Cowboy-Boot = 2
=> Cowboy-Boot = 1 ... (2)

Equation4:
Cowboy-Boot+Horse*HorseShoe = 1+10*2
=>21

Solution:

10

Explanation:
Equation 1 + 9 + 11 = 1 can be derived from
One (o) + nine (n) + eleven (e) = one => 1

Similarly for equation,
12 + 11 + 9
Twelve (t) + eleven (e) + nine (n) => ten (10)

Solution:

Three possible ways are shown in the image below.

Solution:

It can be solve as shown below.

Solution:

30%

Explanation:
√9%
=> √9/√100
=> 3/10
=> 30/100
=> 30%