Advertisements
Advertisements
प्रश्न
If a + b + c = 0 and a2 + b2 + c2 = 16, find the value of ab + bc + ca.
Advertisements
उत्तर
We know that,
`(a + b + c)^2 = a^2 + b^2 + c^2 + 2(ab + bc + ca)`
`=> (0)^2 = 16 + 2(ab + bc + ca)` `[∵ a + b + c = and a^2 + b^2 + c^2 = 16] `
=> 2(ab + bc + ca) = -16
=> ab + bc + ca = -8
APPEARS IN
संबंधित प्रश्न
Evaluate the following using identities:
(399)2
Simplify the following:
322 x 322 - 2 x 322 x 22 + 22 x 22
if `x + 1/x = 11`, find the value of `x^2 + 1/x^2`
If `x^2 + 1/x^2 = 66`, find the value of `x - 1/x`
Simplify the following products:
`(x/2 - 2/5)(2/5 - x/2) - x^2 + 2x`
Simplify the following products:
`(x^3 - 3x^2 - x)(x^2 - 3x + 1)`
Simplify the following expressions:
`(x^2 - x + 1)^2 - (x^2 + x + 1)^2`
If a + b = 10 and ab = 21, find the value of a3 + b3
Evaluate of the following:
463+343
Find the following product:
Evaluate: (9 − y) (7 + y)
Find the squares of the following:
3p - 4q2
Evaluate the following without multiplying:
(999)2
Evaluate the following without multiplying:
(1005)2
Evaluate, using (a + b)(a - b)= a2 - b2.
399 x 401
If a - b = 10 and ab = 11; find a + b.
If x + y = 9, xy = 20
find: x2 - y2.
Using suitable identity, evaluate the following:
1033
Using suitable identity, evaluate the following:
101 × 102
Factorise the following:
9y2 – 66yz + 121z2
