Advertisements
Advertisements
Question
Use the direct method to evaluate :
(xy+4) (xy−4)
Advertisements
Solution
Note: (a+b) (a−b) = a2 − b2
(xy+4) (xy−4) = (xy)2 − (4)2
= x2y2 − 16
APPEARS IN
RELATED QUESTIONS
Factorise the following using appropriate identity:
`x^2 - y^2/100`
Write the following cube in expanded form:
`[3/2x+1]^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:
(1.5x2 − 0.3y2) (1.5x2 + 0.3y2)
If a + b + c = 9 and ab + bc + ca = 23, find the value of a2 + b2 + c2.
If 2x+3y = 13 and xy = 6, find the value of 8x3 + 27y3
Mark the correct alternative in each of the following:
If \[x + \frac{1}{x} = 5\] then \[x^2 + \frac{1}{x^2} = \]
If x + y = 9, xy = 20
find: x2 - y2.
Factorise the following:
25x2 + 16y2 + 4z2 – 40xy + 16yz – 20xz
Without actually calculating the cubes, find the value of:
`(1/2)^3 + (1/3)^3 - (5/6)^3`
