Question

If a+b+c=12 and a²+b²+c²=36 find the value of ab+bc+ca


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Answer 1

Answer:

54

Step-by-step explanation:

(a+b+c)² = a²+b²+c²+2(ab+bc+ca)

(12)²= 36 + 2(ab+bc+ca)

144 - 36 = 2(ab+bc+ca)

108/2 = (ab+bc+ca)

54 = (ab+bc+ca)