Question

20 identities with example?

Answer 1

(a + b) = a + 2ab + b
. (a – b) = a – 2ab + b
. (a + b) (a – b) = a – b
. (x + a) (x + b) = x + (a + b) x + ab
Ex. Expand each of the following :
(i) (2x + 3y)
(ii) (4x – 5y)
(iii) (x + 5) (x + 6)
(iv) (x – 3) (x – 5)
Sol. (i) (2x + 3y) = (2x) + 2.2x.3y + (3y)
[∵ (a + b) = a + 2ab + b ]
= 4x + 12xy + 9y
(ii) (4x – 5y) = (4x) + 2.4x.5y + (5y)2
[∵ (a – b) = a – 2ab + b ]
= 16x – 40xy + 25y
(iii) (x + 5) (x + 6) = x + (5 + 6)x + 5.6
[∵ (x + a) (x + b) = x + (a + b) x + ab]
= x + 11x + 30
(iv) (x – 3) (x – 5) = {x + (–3)} {x + (–5)}
[∵ (x + a) (x + b) = x + (a + b) x + ab]
= x + {(–3) + (–5)}x + (–3).(–5) = x + (–3 – 5)x + 15 = x – 8x + 15

....

Hope it Helps you
Pls mark as BRAINLIAST

Answer 2

hey mate illiaanaa here nd i hope that it helps you. thnx.