Question

Evaluate: b ^2 -9(b-1)^2,if b=1.1

Answer 1

1.1^2-9(1.1-1)^2
=2.2-9×.1^2
=2.2-1.8
=0.4
hope u got it

Answer 2

Step by step solution :

Step  1  :

Trying to factor as a Difference of Cubes:

 1.1      Factoring:  a3-b3 

Theory : A difference of two perfect cubes,  a3 - b3can be factored into
              (a-b) • (a2 +ab +b2)

Proof :  (a-b)•(a2+ab+b2) =
            a3+a2b+ab2-ba2-b2a-b3 =
            a3+(a2b-ba2)+(ab2-b2a)-b3 =
            a3+0+0+b3 =
            a3+b3

Check :  a3 is the cube of   a1