Question

find the perimeter of the following question:

Answer 1

HEY THERE!!


Method of Solution;

1) (21x+13y)²

=> (21x)²+(13y)² +2.12x.13y

=>441x²+169y²+546xy

2) (21x-13y)²

=> (21x)²+(13y)²-2.21x.13y

=> 441x²+169y²-546xy

3) (21x-13y)(21x+13y)

=> (21x)²-(13y)²

=> 441x²-16y²


Hence,

1) ------- B

2)------- C

3) -------A

Answer 2

♠ ANSWER :

1 ). ( 21 x + 13 y ) ²

➡ ( 21 x) ² + ( 13 y ) ² + 2 * 21 x * 13 y.

➡ 441 x² + 169 y ² + 546 xy

⏺️SO, OPTION ( b ) is Correct.

2 ). ( 21 x - 13 ) ²

➡ ( 21 x ) ² + ( 13 y ) ² - 2 * 21 x * 13 y

➡️ 441 x ² + 169 y ² - 546 xy

⏺️So, OPTION ( C ) is correct.

(3 ). ( 21 x - 13 y ) ( 21 x + 13 y )

➡️ ( 21 x )² - ( 13 y )²

➡ 441 x ² - 169 y ².

⏺️So, OPTION ( a ) is correct.