Q3 of 84 Page 4

If a+b+c =0 and a2+b2+c2 =16, find the value of ab + bc + ca.

Using idendity,


Given: a+b+c = 0 and a2 + b2 + c2 =16


Squaring the equation, a+b+c = 0 on both the sides, we get,



More from this chapter

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1

Write the following in the expanded form:

(i) (a + 2b + c)2


(ii) (2a - 3b - c)2


(iii) (-3x + y + z)2


(iv) (m + 2n – 5p)2


(v) (2 + x – 2y)2


(vi) (a2 + b2 + c2)2


(vii) (ab + bc + ca)2


(viii)


(ix)


(x) (x + 2y + 4z)2


(xi) (2x - y + z)2


(xii) (-2x + 3y + 2z)2

 2

Simplify:

(i) (a+b+c)2 +(a-b+c)2


(ii) (a+b+c)2 -(a-b+c)2


(iii) (a+b+c)2 +(a-b+c)2+(a+b-c)2


(iv) (2x+p+c)2-(2x-p+c)2


(v) (x2+y2-z2)2-(x2-y2+z2)2

 4

If a2+b2+c2 =16, and ab + bc + ca=10, find the value of a+b+c.

 5

If a+b+c =9 and ab+bc+ca=23, find the value of a2+b2+c2.