Advertisements
Advertisements
Question
Square of 3x – 4y is ______.
Options
9x2 – 16y2
6x2 – 8y2
9x2 + 16y2 + 24xy
9x2 + 16y2 – 24xy
Advertisements
Solution
Square of 3x – 4y is 9x2 + 16y2 – 24xy.
Explanation:
Square of (3x – 4y) will be (3x – 4y)2.
Comparing (3x – 4y)2 with (a – b)2, we get a = 3x and b = 4y.
Now, using the identity (a – b)2 = a2 – 2ab + b2
(3x – 4y)2 = (3x)2 – 2 · 3x · 4y + (4y)2
= 9x2 – 24xy + 16y2
APPEARS IN
RELATED QUESTIONS
Expand (2)2p − 3q
Expand `("x"-2/"x")^2`
Expand `("a"-1/"a")^2`
1032 – 1022 = ______ × (103 – 102) = ______.
Factorise the following, using the identity a2 – 2ab + b2 = (a – b)2.
x2 – 8x + 16
Factorise the following, using the identity a2 – 2ab + b2 = (a – b)2.
`x^2/4 - 2x + 4`
Factorise the following.
a2 – 16p – 80
The curved surface area of a cylinder is 2π(y2 – 7y + 12) and its radius is (y – 3). Find the height of the cylinder (C.S.A. of cylinder = 2πrh).
If x – y = 13 and xy = 28, then find x2 + y2.
Subtract b(b2 + b – 7) + 5 from 3b2 – 8 and find the value of expression obtained for b = – 3.
