CUET Preparation Today
CUET
General Test
Quantitative Reasoning
Algebra
If x4 + x2y2 + y4 = 105,
x2 + xy + y2 = 21, then
find x2 - xy + y2 .
6
7
4
5
Formula → x4 + y4 + x2y2 = (x2 + y2 + xy) × (x2 + y2 - xy)
⇒ 105 = 21 × (x2 + y2 - xy)
⇒ x2 + y2 - xy = \(\frac{105}{21}\) = 5
