Question

If 25^(3a-2b) = 5^(b-a) = 5² and , then find the value of ab - c.

• A. 1
• B. 0
• C. -1
• D. -2

Answer 1

The Correct Option is B

The correct option is (B): 0.
25^(3a-2b) = 5^(b-a) = 5²
52 ^(3a-2b) = 5^(b-a) = 5²
5(^6a-4b) = 5^(b-a) = 5²
5^(6a-4b) = 5²
6a - 4b = 2
3a - 2b = 1 .............. (1)
5^(b-a) = 52
b - a = 2
2b - 2a = 4 .............. (2)
From (1) and (2):
3a - 2a - 4 = 1
a = 5
b = 7
Now,
c= 35
value of ab - c
= 5 * 7 - 35
= 35 - 35
= 0