Question

Find the value of a + b -2c when a=3, b=2 and c= -1​

Answer 1

Step-by-step explanation:

We know that

a

3

+b

3

+c

3

−3abc=(a+b+c)(a

2

+b

2

+c

2

−ab−bc−ca)

As a+b+c=0, so, a

3

+b

3

+c

3

−3abc=(0)(a

2

+b

2

+c

2

−ab−bc−ca)=0

Hence, a

3

+b

3

+c

3

=3abc.

Answer 2

$3 + 2 - 2 \times - 1$

$5 - ( - 2)$

$5 + 2 = 7$

So 7 is solution