Evaluate the following products without multiplying directly:
(i) 
(ii) 
(iii) 
(i) Using identity,
(x + a) (x + b) = x2 + (a + b) x + ab
Here, x = 100, a = 3 and b = 7
103 * 107 = (100 + 3) (100 + 7)
= (100)2 + (3 + 7) 100 + (3 * 7)
= 10000 + 1000 + 21
= 11021
(ii) Using identity,
(x + a) (x + b) = x2 + (a + b) x + ab
Here, x = 90, a = 5 and b = 4
95 * 96 = (90 + 5) (90 + 4)
= (90)2 + (3 + 7) 90 + (5 * 6)
= 8100 + 990 + 30
= 9120
(iii) Using identity,
(x + y) (x – y) = x2 – y2
Here, x = 100 and y = 4
104 * 96 = (100 + 4) (100 – 4)
= (100)2 – (4)2
= 10000 – 16
= 9984
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