Solution:

The solution is:
547809 + 087549 + 780954 = 1416312

Solution:

    35997
+ 284508
========
    320505
========

Solution:

17

Explanation :
The relationship holds for below formula :
pow(x,3) - pow(x,2) - 1
=> 9*9*9 - 9*9 - 1
=> 729 - 81 - 1
=> 647

Similarly,
17*17*17 - 17*17 - 1
=> 4913 - 289 - 1
=> 4623

Solution:

In the given statement, the letters represent their equivalent position in the alphabets.
A + A = 1 + 1 = 2 = B
B + B = 2 + 2 = 4 = D
A + D = 1 + 4 = 5 = E

Hence,
B + D + E = 2 + 4 + 5 = 11 = K

Solution:

Yes, show in below picture

Solution:

HEAVEN

Explanation:
ENEMY = 4 + 3 + 4 + 4 + 3 = 18
LINK = 2 + 1 + 3 + 3 = 9
HELL = 3 + 4 + 2 + 2 = 11
TAXI = 2 + 3 + 2 + 1 = 8
HEAVEN = 3 + 4 + 3 + 2 + 4 + 3 = 19

Using the same trick,
TAXI + HELL = 8 + 11 = 19 = HEAVEN.

Therefore, the required answer is HEAVEN.

Solution:

T = 1
W = 3
O = 8
H = 9
R = 0
E = 4

For the full multiplication, see the figure.

Solution:

22 + 2 = 24

Solution:

6

Explanation:
(2^x)(30^3) = (2^3) (3^3) (4^3) (5^3)

(2^x)(30^3) = (120^3)

(2^x) = (120^3)/ (30^3)

(2^x) = (4^3)

(2^x) = 64

ln(2^x) = ln(64)

x ln(2) = ln(64)

x = ln(64)/ln(2)

x = 6

Thus x = 6.

Solution:

    526485
+ 197485
= 723970