Advertisements
Advertisements
Question
If a + b = 8 and ab = 6, find the value of a3 + b3
Advertisements
Solution
In the given problem, we have to find the value of `a^3 +b^3`
Given `a+b = 8.ab = 6`
We shall use the identity `a^3 + b^3 = (a+b)^3 ab(a+b)`
`a^3 + b^3 = (a+b)^3- 3ab (a+b)`
`a^3 +b^3 = a(8)^3 - 3 3 xx 6 (8)`
`a^3 +b^3 = 512 - 144`
`a^3+b^3 = 368`
Hence the value of i`a^3 +b^3` is 368 .
APPEARS IN
RELATED QUESTIONS
Expand the following, using suitable identity:
(–2x + 3y + 2z)2
Evaluate the following using suitable identity:
(102)3
What are the possible expressions for the dimensions of the cuboids whose volume is given below?
| Volume : 3x2 – 12x |
If 3x - 7y = 10 and xy = -1, find the value of `9x^2 + 49y^2`
Simplify `(x^2 + y^2 - z)^2 - (x^2 - y^2 + z^2)^2`
Find the cube of the following binomials expression :
\[\frac{1}{x} + \frac{y}{3}\]
If \[x - \frac{1}{x} = 5\], find the value of \[x^3 - \frac{1}{x^3}\]
Evaluate of the following:
(598)3
Find the following product:
(4x − 5y) (16x2 + 20xy + 25y2)
Find the following product:
If x = 3 and y = − 1, find the values of the following using in identify:
\[\left( \frac{3}{x} - \frac{x}{3} \right) \left( \frac{x^2}{9} + \frac{9}{x^2} + 1 \right)\]
If x = 3 and y = − 1, find the values of the following using in identify:
\[\left( \frac{5}{x} + 5x \right)\] \[\left( \frac{25}{x^2} - 25 + 25 x^2 \right)\]
If x + \[\frac{1}{x}\] = then find the value of \[x^2 + \frac{1}{x^2}\].
Evaluate: (2 − z) (15 − z)
Evaluate: `(2"a"+1/"2a")(2"a"-1/"2a")`
Evaluate: (1.6x + 0.7y) (1.6x − 0.7y)
Evaluate, using (a + b)(a - b)= a2 - b2.
399 x 401
If `"a"^2 + (1)/"a"^2 = 14`; find the value of `"a" + (1)/"a"`
If `"p" + (1)/"p" = 6`; find : `"p"^2 + (1)/"p"^2`
