Using a2 − b2 = (a + b) (a − b), find(i) 512 − 492 (ii) (1.02)2

1.	Using a2 − b2 = (a + b) (a − b), find(i) 512 − 492 (ii) (1.02)2 − (0.98)2
Answer» (i) 51²− 49² = (51 + 49) (51 − 49) = (100) (2) = 200 (ii) (1.02)² − (0.98)² = (1.02 + 0.98) (1.02 − 0.98) = (2) (0.04) = 0.08

Using a2 − b2 = (a + b) (a − b), find(i) 512 − 492 (ii) (1.02)2 − (0.98)2

Answer»

(i) 51²− 49² = (51 + 49) (51 − 49)

= (100) (2) = 200

(ii) (1.02)² − (0.98)² = (1.02 + 0.98) (1.02 − 0.98) = (2) (0.04) = 0.08

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