Advertisements
Advertisements
Question
If m – n = 16 and m2 + n2 = 400, then find mn.
Advertisements
Solution
Given, m – n = 16 and m2 + n2 = 400.
Since, (m – n)2 = m2 + n2 = 2mn ...[Using the identity, (a – b)2 = a2 + b2 – 2ab]
∴ (16)2 = 400 – 2mn
⇒ 2mn = 400 – (16)2
⇒ 2mn = 400 – 256
⇒ 2mn = 144
⇒ `mn = 144/2`
⇒ mn = 72
APPEARS IN
RELATED QUESTIONS
(p – q)2 = _______________
Using identity, find the value of (4.9)2
A square lawn has a 2 m wide path surrounding it. If the area of the path is 136 m2, find the area of lawn
a2 – b2 is equal to ______.
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.
p2 – 2p + 1
Factorise the following, using the identity a2 – 2ab + b2 = (a – b)2.
`9y^2 - 4xy + (4x^2)/9`
Factorise the following.
x2 – 17x + 60
Verify the following:
(a – b)(a – b)(a – b) = a3 – 3a2b + 3ab2 – b3
If `x - 1/x = 7` then find the value of `x^2 + 1/x^2`.
