Advertisements
Advertisements
प्रश्न
If a + b = 10 and ab = 21, find the value of a3 + b3
उत्तर
In the given problem, we have to find the value of `a^3 + b^3`
Given `a+b = 10, ab = 21`
We shall use the identity `(a+b)^3 = a^3 +b^3 +3ab(a+b)`
Here putting, `a+b = 10,ab= 21`
`(10)^3 = a^3+ b^3 +3 (21)(10)`
` 1000 = a^3 +b^3 +630`
`1000 - 630 = a^3 +b^3`
`370 = a^3 + b^3`
Hence the value of `a^3 +b^3` is 370.
APPEARS IN
संबंधित प्रश्न
Write the following cube in expanded form:
`[3/2x+1]^3`
Evaluate the following using suitable identity:
(102)3
Factorise the following:
64a3 – 27b3 – 144a2b + 108ab2
Find the value of 64x3 − 125z3, if 4x − 5z = 16 and xz = 12.
Simplify of the following:
(2x − 5y)3 − (2x + 5y)3
If \[x^4 + \frac{1}{x^4} = 194,\] find \[x^3 + \frac{1}{x^3}, x^2 + \frac{1}{x^2}\] and \[x + \frac{1}{x}\]
If a + b = 8 and ab = 6, find the value of a3 + b3
If x + y + z = 8 and xy +yz +zx = 20, find the value of x3 + y3 + z3 −3xyz
(a − b)3 + (b − c)3 + (c − a)3 =
If \[\frac{a}{b} + \frac{b}{a} = - 1\] then a3 − b3 =
If a2 + b2 + c2 − ab − bc − ca =0, then
Evaluate: (5xy − 7) (7xy + 9)
Expand the following:
(2x - 5) (2x + 5) (2x- 3)
If p + q = 8 and p - q = 4, find:
pq
If m - n = 0.9 and mn = 0.36, find:
m2 - n2.
If x + y + z = 12 and xy + yz + zx = 27; find x2 + y2 + z2.
If a2 + b2 + c2 = 41 and a + b + c = 9; find ab + bc + ca.
If p2 + q2 + r2 = 82 and pq + qr + pr = 18; find p + q + r.
Simplify:
`(x - 1/x)(x^2 + 1 + 1/x^2)`
Simplify:
(2x - 4y + 7)(2x + 4y + 7)
