Find the H.C.F of the following expressions.
1) 16x⁴ - 4x² - 4x - 1 , 8x³ - 1
2) 9x² - 4y² - 8yz - 4z² , 4z² - 4y² - 9x² - 12xy , 9x² + 12xz + 4z² - 4y²
3) x² - 18x - 19 + 20y - y² , x² + x - y² + y , x² - y² + 2y - 1
Irrelevant / Random answers will be reported !!