Advertisements
Advertisements
प्रश्न
If a − b = 5 and ab = 12, find the value of a2 + b2
Advertisements
उत्तर
We have to find the value `a^2 +b^2`
Given a-b = 5, ab = 12
Using identity `(a - b)^2 = a^2 - 2ab +b^2`
By substituting the value of a-b = 5 ,ab = 12 we get ,
`(5)^2 = a^2 +b^2 - 2 xx 12`
`5 xx 5 = a^2 +b^2 - 2 xx 12`
`25 = a^2 +b^2 -24`
By transposing – 24 to left hand side we get
`25 + 24 = a^2 +b^2`
`49 = a^2 +b^2`
Hence the value of `a^2 +b^2` is 49.
APPEARS IN
संबंधित प्रश्न
Without actually calculating the cubes, find the value of the following:
(–12)3 + (7)3 + (5)3
Without actually calculating the cubes, find the value of the following:
(28)3 + (–15)3 + (–13)3
What are the possible expressions for the dimensions of the cuboids whose volume is given below?
| Volume : 12ky2 + 8ky – 20k |
Evaluate the following using identities:
(399)2
Simplify the following:
322 x 322 - 2 x 322 x 22 + 22 x 22
Simplify the following:
0.76 x 0.76 - 2 x 0.76 x 0.24 x 0.24 + 0.24
If 2x + 3y = 8 and xy = 2 find the value of `4x^2 + 9y^2`
Find the following product:
(7p4 + q) (49p8 − 7p4q + q2)
If x + y + z = 8 and xy +yz +zx = 20, find the value of x3 + y3 + z3 −3xyz
If a + b + c = 0, then write the value of \[\frac{a^2}{bc} + \frac{b^2}{ca} + \frac{c^2}{ab}\]
If \[\frac{a}{b} + \frac{b}{a} = - 1\] then a3 − b3 =
Use the direct method to evaluate :
(3x2+5y2) (3x2−5y2)
Use the direct method to evaluate :
`("a"/2-"b"/3)("a"/2+"b"/3)`
If `x + (1)/x = 3`; find `x^4 + (1)/x^4`
If `"a"^2 - 7"a" + 1` = 0 and a = ≠ 0, find :
`"a"^2 + (1)/"a"^2`
If `"a"^2 + (1)/"a"^2 = 14`; find the value of `"a" + (1)/"a"`
If `x^2 + (1)/x^2 = 18`; find : `x - (1)/x`
Factorise the following:
4x2 + 20x + 25
Factorise the following:
9x2 + 4y2 + 16z2 + 12xy – 16yz – 24xz
