2025 · Q16
What is the HCF of x^3+y^3+3xy-1 and [the second polynomial could not be verified from available sources]?
Elementary MathematicsHCF and LCM
- Ax+y
- Bx+y+1
- Cx+y-1
- D1
Explanation
The stem asks for the HCF of x^3+y^3+3xy-1 and a second polynomial that could not be recovered. (Note x^3+y^3+3xy-1=(x+y-1)(x^2+y^2+1-xy+x+y), so x+y-1 divides the first polynomial.) The key is taken from the published coaching key (PW, CDS 2 2025 Set A: C, i.e. x+y-1). Note: key disputed - independent verification inconclusive.