Advertisements
Advertisements
प्रश्न
If 2x + 3y = 10 and xy = 5; find the value of 4x2 + 9y2
Advertisements
उत्तर
Given 2x + 3y = 10 and xy = 5
4x2 +9y2
= (2x2) + (3y)2
= (2x + 3y)2 - 2(2x)(3y)
......[∵ (a + b)2 + a2 + b2 + 2ab, so, a2 + b2 = (a + b)2 - 2ab]
= (10)2 - 12(5)
= 100 - 60
= 40.
APPEARS IN
संबंधित प्रश्न
Evaluate the following using suitable identity:
(99)3
Evaluate the following using identities:
117 x 83
Simplify the expression:
`(x + y + z)^2 + (x + y/2 + 2/3)^2 - (x/2 + y/3 + z/4)^2`
Simplify the following expressions:
`(x + y - 2z)^2 - x^2 - y^2 - 3z^2 +4xy`
Simplify the following expressions:
`(x^2 - x + 1)^2 - (x^2 + x + 1)^2`
If \[a^2 + \frac{1}{a^2} = 102\] , find the value of \[a - \frac{1}{a}\].
If a + `1/a`= 6 and a ≠ 0 find :
(i) `a - 1/a (ii) a^2 - 1/a^2`
Use the direct method to evaluate :
(ab+x2) (ab−x2)
Evaluate: (5xy − 7) (7xy + 9)
If a + b + c = 9 and ab + bc + ca = 26, find a2 + b2 + c2.
