Advertisements
Advertisements
Question
Use the direct method to evaluate :
(xy+4) (xy−4)
Sum
Advertisements
Solution
Note: (a+b) (a−b) = a2 − b2
(xy+4) (xy−4) = (xy)2 − (4)2
= x2y2 − 16
shaalaa.com
Is there an error in this question or solution?
APPEARS IN
RELATED QUESTIONS
Factorise the following using appropriate identity:
`x^2 - y^2/100`
Verify that `x^3+y^3+z^3-3xyz=1/2(x+y+z)[(x-y)^2+(y-z)^2+(z-x)^2]`
Prove that a2 + b2 + c2 − ab − bc − ca is always non-negative for all values of a, b and c
Write in the expanded form:
`(2 + x - 2y)^2`
If x = 3 and y = − 1, find the values of the following using in identify:
\[\left( \frac{5}{x} + 5x \right)\] \[\left( \frac{25}{x^2} - 25 + 25 x^2 \right)\]
Evaluate:
(0.2)3 − (0.3)3 + (0.1)3
If \[x^2 + \frac{1}{x^2} = 102\], then \[x - \frac{1}{x}\] =
If \[\frac{a}{b} + \frac{b}{a} = - 1\] then a3 − b3 =
If a + b = 7 and ab = 10; find a - b.
Evaluate: `(4/7"a"+3/4"b")(4/7"a"-3/4"b")`
