Question

If a²+b²+c²=29 and a+b+c = 9 find ab+bc+ca
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Answer 1

Answer:

26

Step-by-step explanation:

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

Substituting a²+b²+c²=29 & (a+b+c) = 9

29 = 9² - 2(ab + bc + ca)

29 = 81 - 2(ab + bc + ca)

81-29 = 2(ab+bc+ca)

52 = 2(ab + bc + ca)

52/2 = ab+bc+ca

26 = ab + bc + ca

ab + bc + ca = 26

(Please mark my answer as brainliest)