If a + 2b = 10 and 2ab = 9, then |a - 2b

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Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If a + 2b = 10 and 2ab = 9, then |a - 2b| is equal to:

Options:

Correct Answer:

Explanation:

If a + 2b = 10

2ab = 9,

ab = 4.5

then |a - 2b|= ?

If x + y = n

then, x - y = \(\sqrt {n^2 - 4× x × y}\)

= |a - 2b| = \(\sqrt {10^2 - 4× 2 × 4.5}\) = \(\sqrt {100 - 36}\) = 8