Question

Special Products where a is the 1st term and b is the second term

✓(a + b)(a − b) = a²-b²

✓(a + b)²=a²+2ab + b²

✓(a + b)³= a³± 3a²b+3ab² + b³

✓(a²- ab + b²) (a + b) =a³ + b³

✓(a² + ab + b²) (a - b) =a³-b³​

Answer 1

Answer:

(i) X= { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday , Saturday} 

The set X contains all the days of a week.

Hence in set builder form, we write

X= { x:x is a day in a week }

(ii) A={1,21,31,41,51,...}. The denominators of the elements are 1,2,3,4,...

∴ The set-builder form is A={x:x=n1,n∈N}

Answer 2

Answer:

a³ + b³ = (a + b)(a² – ab + b²)

WHY?

BECAUSE:—

(a + b)³ = a³ + 3ab(a + b) + b³

then a³ + b³ = (a + b)³ – 3ab(a + b)

= (a + b)[(a + b)² – 3ab]

= (a + b)(a² + 2ab + b² – 3ab)

= (a + b)(a² – ab + b² )

I HOPE YOU ARE SATISFIED WITH THE ANSWER