Question

B) If (a - b) = 4 and ab = 2, find the value of a² + b².

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Answer 1

20

Explanation:

note that

(a - b)² = a² + b² - 2ab , thus

a² + b² - 2ab = (a - b)² ( add 2ab to both sides )

a² + b² = (a - b)² + 2ab = 4² + 2(2) = 16 + 4 = 20