Question

Simplify (7+√5)^2-(7-√5)^2

Answer 1

Answer:

( 7 + √5 )² - ( 7 - √5 )²

Using identity ;

a² - b² = (a + b)(a - b)

( 7 + √5 )² - ( 7 - √5 )²

(7 + √5 + 7 - √5 ) ( 7 + √5 - 7 + √5 )

14 * 2√5

28√5

___________

Answer 2

(a+b)^2 - (a-b)^2=4ab

(7+√5)^2 - (7-√5)^2 =4(7)(√5)=28√5