Use the formula to multiply the following: i. (x + y)(x – y) ii. (

1.	Use the formula to multiply the following: i. (x + y)(x – y) ii. (3x – 5)(3x + 5) iii. (a + 6)(a – 6iv. (x/5 + 6) (x/5 - 6)
Answer» i. Here, a = x, b = y (x + y)(x – y) = x² – y² …. [(a + b)(a – b) = a² – b² ] ii. Here, a = 3x, b = 5 (3x – 5) (3x + 5) = (3x)² – 5² …. [(a + b)(a – b) = a² – b² ] = 9x² – 25 iii. Here, A = a, B = 6 (a + 6) (a – 6) = a² – 6² …. [(A + B)(A – B) = A² – B² ] = a² – 36 iv. Here, a = x/2 , b = 6 (x/5 + 6) (x/5 - 6) = (x/5)² - (6)²…. [(a + b)(a – b) = a² – b² ] = x² /25 - 36

Use the formula to multiply the following: i. (x + y)(x – y) ii. (3x – 5)(3x + 5) iii. (a + 6)(a – 6iv. (x/5 + 6) (x/5 - 6)

Answer»

i. Here, a = x, b = y

(x + y)(x – y) = x² – y² …. [(a + b)(a – b) = a² – b² ]

ii. Here, a = 3x, b = 5

(3x – 5) (3x + 5) = (3x)² – 5² …. [(a + b)(a – b) = a² – b² ]

= 9x² – 25

iii. Here, A = a, B = 6

(a + 6) (a – 6) = a² – 6² …. [(A + B)(A – B) = A² – B² ]

= a² – 36

iv. Here, a = x/2 , b = 6

(x/5 + 6) (x/5 - 6) = (x/5)² - (6)²…. [(a + b)(a – b) = a² – b² ]

= x² /25 - 36