Question

Using suitable identities, find the
I product of the following:
a) (3x-y-4) (3x - y + 5)​

Answer 1

Step-by-step explanation:

[ ( 3x- y) -4] [ ( 3x -y) +5]

using the property ( p+a) ( p+b) = p^2 + ( a+b) *p + ab

here p = ( 3x-y )

a = -4

b = 5

put the values

( 3x-y) ^2 + ( -4+5) ( 3x-y) + (-4)*5

( 3x-y) ^2 + (3x-y) -20

9x^2 +y^2 -6xy + 3x -y -20 ( using (q-r)^2 = q^2 + r^2 - 2qr)