Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If x4 + x2y2 + y4 = 15,

x2 + xy + y2 = 5, then

find x2 - xy + y2 .

Options:

5

7

4

3

Correct Answer:

3

Explanation:

Formula → x4 + y4 + x2y2 = (x+ y2 + xy) × (x+ y2 - xy)

⇒ 15 = 5 × (x+ y2 - xy)

⇒ x+ y2 - xy = \(\frac{15}{5}\) = 3