Q.1 If a + b + c = 15 ab+bc+ca =81 . Find the value of a^ 2 +b^ 2 +c^ 2 =? Options 62 63 64 65
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Answered by
1
Answer:
Correct option is
A
6
Formula,
(a+b+c)
2
=a
2
+b
2
+c
2
+2ab+2bc+2ca
⇒(a+b+c)
2
=a
2
+b
2
+c
2
+2(ab+bc+ca)
Given,
ab+bc+ca=10,a
2
+b
2
+c
2
=16
⇒(a+b+c)
2
=16+2(10)
a+b+c=
16+20
=6
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