Question

Please Help

Answer 1

Answer:

Option c $4l^2-81$

Explanation:

As we have given in the question  

$Sum=(2l+9)\times(2l-9)$

So by using the formula

$(a-b) (a+b) = a^2+ab-ba-b^2$

So the equation will become

$(a+b)(a-b)=a^2-b^2$

So according to question,  we have ,

a = 2l and b = 9

So,

$(2l+9)(2l-9)=(4l^2-81)$

And required Sum=$(4l^2-81)$

So the final answer of the question which is required is  Sum=$(4l^2-81)$

Answer 2

Answer:(b). 4I2-81

Step-by-step explanation:(2I+9)(2I-9)

=4I2-18I+18I-81

=4I2-81