Advertisements
Advertisements
प्रश्न
If 2x + 3y = 8 and xy = 2 find the value of `4x^2 + 9y^2`
Advertisements
उत्तर
`(2x + 3y)^2 = (2x)^2 + (3y)^2 + 2(2x)(3y)`
`=> (2x + 3y)^2 = 4x^2 - 9y^2 + 12xy`
`=> (8)^2 = (4x^2 + 9y^2 + 24)` [∵ 2x + 3y = 8, xy = 24]
`=> 64 - 24 = 4x^2 + 9y^2`
`=> 4x^2 + 9y^2 = 40`
APPEARS IN
संबंधित प्रश्न
Evaluate the following using identities:
(399)2
Evaluate following using identities:
991 ☓ 1009
If a − b = 4 and ab = 21, find the value of a3 −b3
Evaluate the following:
(98)3
Evaluate of the following:
1043 + 963
Simplify of the following:
(2x − 5y)3 − (2x + 5y)3
If x = 3 and y = − 1, find the values of the following using in identify:
\[\left( \frac{x}{7} + \frac{y}{3} \right) \left( \frac{x^2}{49} + \frac{y^2}{9} - \frac{xy}{21} \right)\]
Evaluate:
483 − 303 − 183
If \[x^3 - \frac{1}{x^3} = 14\],then \[x - \frac{1}{x} =\]
If a2 + b2 + c2 − ab − bc − ca =0, then
If a2 - 5a - 1 = 0 and a ≠ 0 ; find:
- `a - 1/a`
- `a + 1/a`
- `a^2 - 1/a^2`
Use the direct method to evaluate the following products:
(5a + 16) (3a – 7)
Evaluate: 203 × 197
Expand the following:
(m + 8) (m - 7)
Evaluate the following without multiplying:
(1005)2
If m - n = 0.9 and mn = 0.36, find:
m + n
If `"a"^2 - 7"a" + 1` = 0 and a = ≠ 0, find :
`"a"^2 + (1)/"a"^2`
If x + y + z = p and xy + yz + zx = q; find x2 + y2 + z2.
Simplify:
(7a +5b)2 - (7a - 5b)2
The value of 2492 – 2482 is ______.
