Advertisements
Advertisements
Question
Using the identity (a + b)(a – b) = a2 – b2, find the following product
(4 – mn)(mn + 4)
Advertisements
Solution
(4 – mn)(mn + 4)
(4 – mn)(mn + 4) can be written as (4 – mn) (4 + mn = (4 + mn)(4 – mn)
Substituting a = 4 and b = mn
In (a + b)(a – b) = a2 – b2, we get
(4 + mn)(4 – mn) = 42 – (mn)2
= 16 – m2 n2
APPEARS IN
RELATED QUESTIONS
(5 + 20)(–20 – 5) = ?
Using identity, find the value of (1.9) × (2.1)
Using suitable identities, evaluate the following.
(132)2 – (68)2
Factorise the following using the identity a2 – b2 = (a + b)(a – b).
28ay2 – 175ax2
Factorise the following using the identity a2 – b2 = (a + b)(a – b).
(x + y)4 – (x – y)4
Factorise the following using the identity a2 – b2 = (a + b)(a – b).
9x2 – (3y + z)2
Factorise the expression and divide them as directed:
(x3 + x2 – 132x) ÷ x(x – 11)
Factorise the expression and divide them as directed:
(3x2 – 48) ÷ (x – 4)
The base of a parallelogram is (2x + 3 units) and the corresponding height is (2x – 3 units). Find the area of the parallelogram in terms of x. What will be the area of parallelogram of x = 30 units?
Verify the following:
(m + n)(m2 – mn + n2) = m3 + n3
