Question

If a^2+b^2+c^2 is 29 and a+b+c is 9 Find ab+bc+ca

Answer 1

Step-by-step explanation:

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

(9)^2=29+2(ab+bc+ca)

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

52÷2=ab+bc+ca

26=ab+bc+c

a3+b3+c3-3abc=(a+b+c)(a2+b2+c2-ab+bc-ca)

=(9)(29-26)

=9(3)

=27. ans

Step-by-step explanation:

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