Answer:
(a) 10×8
(b) 31×9
Step-by-step explanation:
We have given that
(a) 81 - 1
We have to write this in form of product of two integers
We know the algebraic equation [tex]a^2-b^2=(a+b)(a-b)[/tex]
As 81 -1 can be written as [tex]9^2-1^2[/tex]
So [tex]9^2-1^2=(9+1)(9-1)=10\times 8[/tex]
(b) We have given 400 - 121
We have to write this in form of product of two integers
We know the algebraic equation [tex]a^2-b^2=(a+b)(a-b)[/tex]
As 81 -1 can be written as [tex]{20}^2-{11}^2[/tex]
So [tex]{20}^2-{11}^1=(20+11)(20-11)=31\times 9[/tex]
