Question

evaluate the following using suitable identities 82×85

Answer 1

82 × 85

(80+2)(80+5)

80(80+5) + 2(80+5)

6400 + 400 + 160 + 10

6970

Answer 2

Answer:

6970

Explanation;

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We know the algebraic identity:

(x+a)(x+b) = x²+(a+b)x+ab

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Given,

82×85

= (80+2)(80+5)

Here, x = 80, a=2 ,b=5

= 80² + (2+5)80+2×5

= 6400 + 7×80 + 10

= 6400 + 560 + 10

= 6970

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