Question

Can you please find thw answer of this question.
Add the algebraic expression it in each case of the following
9a×9a and -2a × -2a​

Answer 1

Answer:

${9a}^{2} + {( - 2a}^{2} ) \\ = {9a}^{2} - {2a}^{2} \\ = {7a}^{2}$

Answer 2

Remember:

-,- = +

+,-= -

-,+ = -

+,+= +

Therefore:

9a x 9a

9 x 9 = 81

a x a = a^2

9a^2 = 81a^2

-2a x -2a

-2 x -2 = 4

a x a = a^2

-2a^2 = 4a^2

note: no offence meant <3 but in case you don't know which I'm sure you do, ^2 means raise to power 2 :)

81a^2 + 4a^2

--> now simply add 81 and 4

a^2 + a^2 will remain the same

a^2 + a^2 = a^2

81a^2 + 4a^2 = 85a^2