Advertisements
Advertisements
प्रश्न
If a − b = −8 and ab = −12, then a3 − b3 =
पर्याय
−244
−240
−224
−260
Advertisements
उत्तर
To find the value of a3 − b3
Given `a-b = -8,ab =-12`
Using identity `(a-b)^3 = a^3 - b^3 -3ab(a-b)`
Here `a-b = -8,ab =-12`we get
`(-8)^3 = a^3 -b^3 -3ab(a-b)`
`(-8)^3 =a^3 -b^3 -3 xx -12 xx -8`
`-512 = a^3 -b^3 - 288`
Transposing -288 to left hand side we get
`- 512 + 288 = a^3 - b^3`
`-224 = a^3 - b^3`
Hence the value of `a^3 -b^3 `is -224 .
APPEARS IN
संबंधित प्रश्न
Simplify the following products:
`(1/2a - 3b)(1/2a + 3b)(1/4a^2 + 9b^2)`
Simplify `(x^2 + y^2 - z)^2 - (x^2 - y^2 + z^2)^2`
If \[x - \frac{1}{x} = 5\], find the value of \[x^3 - \frac{1}{x^3}\]
Find the following product:
\[\left( \frac{3}{x} - \frac{5}{y} \right) \left( \frac{9}{x^2} + \frac{25}{y^2} + \frac{15}{xy} \right)\]
Find the following product:
Find the following product:
(3x + 2y + 2z) (9x2 + 4y2 + 4z2 − 6xy − 4yz − 6zx)
\[\frac{( a^2 - b^2 )^3 + ( b^2 - c^2 )^3 + ( c^2 - a^2 )^3}{(a - b )^3 + (b - c )^3 + (c - a )^3} =\]
Use the direct method to evaluate the following products :
(3x – 2y) (2x + y)
Use the direct method to evaluate the following products :
(8 – b) (3 + b)
Use the direct method to evaluate :
`("a"/2-"b"/3)("a"/2+"b"/3)`
Evaluate: (5xy − 7) (7xy + 9)
Evaluate: `(2"x"-3/5)(2"x"+3/5)`
If x + y = 9, xy = 20
find: x2 - y2.
If p + q = 8 and p - q = 4, find:
pq
If m - n = 0.9 and mn = 0.36, find:
m + n
If x + y + z = p and xy + yz + zx = q; find x2 + y2 + z2.
Simplify:
`(x - 1/x)(x^2 + 1 + 1/x^2)`
Simplify:
(1 + x)(1 - x)(1 - x + x2)(1 + x + x2)
Simplify:
(3a + 2b - c)(9a2 + 4b2 + c2 - 6ab + 2bc +3ca)
Factorise the following:
4x2 + 20x + 25
