Question

formula of (x-y-1)^2​

Answer 1

Answer:

x^2 + y^2 + 1 - 2xy + 2y - 2x

Step-by-step explanation:

( x - y - 1 )^2​

It is similar like the formula ( a + b + c )^2

( a + b + c )^2 = a^2 + b^2 + c^2 + 2 ( ab + bc + ca )

Here,

a = x

b = - y

c = - 1

ab = - xy

bc = y

ac = - x

( x - y - 1 )^2​ = x^2 + ( - y )^2 + ( - 1 )^2 + 2 ( - xy + y - x )

( x - y - 1 )^2 = x^2 + y^2 + 1 - 2xy + 2y - 2x

Answer 2

${\boxed{\underline{\huge{\pink{\sf \: Solution :-}}}}}$

Formula of (x + y + z)² = x² y² + z² + 2xy + 2yz + 2xz

by putting suitable values we can find the expansion of (x - y -1)² as

= x² + y² + 1 - 2xy - 2x + 2y

Hope that this will help you