Question

1-2ab - (a2+b2)pls factorise this

Answer 1

1-2ab-a²-b²

multiplying by -

a²+b²+2ab-1

(a+b)²-1

Answer 2

$Given \: 1 - 2ab - ( a^{2} + b^{2} )$

$= 1 - ( 2ab + a^{2} + b^{2} )$

$= 1^{2} - ( a + b )^{2}$

$= [ 1 + ( a + b ) ] [ 1 - ( a + b ) ]$

$= ( 1 + a + b )( 1 - a - b )$

Therefore.,

$\red{ Factors \: of \: 1 - 2ab - ( a^{2} + b^{2} )}$

$\green { = ( 1 + a + b )( 1 - a - b )}$

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