MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Expansion of (x+y+z)^2

If a + b + c ...

Question

If a + b + c = 11 and $a^{2} + b^{2} + c^{2} = 81$ , find ; $a b + b c + c a$ .

Open in App

Solution

Since $(a + b + c)^{2} = a^{2} + b^{2} + c^{2} + 2 (a b + b c + c a) ∴ (11)^{2} = 81 + 2 (a b + b c + c a) ∴ 2 (a b + b c + c a) = 121 - 81 = 40 a b + b c + c a = \frac{40}{2} \Rightarrow a b + b c + c a = 20$

Suggest Corrections

thumbs-up

25

Similar questions

a + b + c = 6

a b + b c + c a = 11

(a^{2} + b^{2} + c^{2})

Q. If a² + b² + c² + ab + bc + ca = 89 and (a + b) : (b + c) : (c + a) = 12 : 5 : 3, where a, b and c are real numbers, then (a² + b² + c² – ab – bc – ca) equals

यदि a² + b² + c² + ab + bc + ca = 89 तथा (a + b) : (b + c) : (c + a) = 12 : 5 : 3, जहाँ a, b व c वास्तविक संख्याएँ हैं, तब (a² + b² + c² – ab – bc – ca) बराबर है

Q. If a+b+c=0 what is the value of

\frac{a^{2} + b^{2} + a b}{b^{2} + c^{2} + b c} + \frac{c^{2} + c a + a^{2}}{b^{2} + c^{2} + b c}

Find $a^{2} + b^{2} + c^{2}; i f a + b + c = 9 a n d a b + b c + c a = 24$

Q. If a² + b² + c² = 250 and ab + bc + ca = 3, find a + b + c.

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

(x+y+z)^2

MATHEMATICS

Watch in App

explore_more_icon

Explore more

Expansion of (x+y+z)^2

Standard VIII Mathematics

Join BYJU'S Learning Program

CrossIcon