If the highest common factor (HCF) of x and y is 15, then the HCF of 36x2 - 81y2 and 81x2-9y2 is divisible by_________.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 135
Given that
If the highest common factor (HCF) of x and y is 15
The HCF of 36x2 - 81y2 and 81x2-9y2
36x2 - 81y2 = 9 (2x + 3y)(2x - 3y)
81x2 - 9y2 = 9 (3x + y) (3x -y)
the HCF = 9
Hence, the HCF of 36x2 - 81y2 and 81x2 - 9y2 is divisible by = 9 × 15 = 135