Question

a+b+c (ii) 1/a+1/b+1/c (iii) a²+b²+c².​

Answer 1

Step-by-step explanation:

(1−a)(1−c−b+bc)

=1−c−b+bc−a+ac+ab

=1−(a+b+c)+(ab+bc+ac)

=1−1+ab+bc+ac

=

2

2(ab+bc+ac)

=

2

(a+b+c)

2

−(a

2

+b

2

+c

2

)

=

2

1−21

=−10