If a + b + c = 7, a2 + b2 + c2

CUET Preparation Today

Start Free Mocks

Home Questions ED6PF256TD

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If a + b + c = 7, a² + b² + c² = 21 , then the value of (ab + bc + ca) is?

Options:

Correct Answer:

Explanation:

(a + b + c)² = a² + b² + c² + 2(ab + bc + ca)

(7)² = 21 + 2(ab + bc + ca)

49 - 21 = 2(ab + bc + ca)

(ab + bc + ca) = 14