Question

(b) Find 51x41 using the principal (x+1)(y+1)
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Answer 1

Given:-

51 × 41

Principal used:-

(x+1)(y+1) = $x^2 +2x +1$

Identity to be used:-

$(x+a)(x+b) = x^2 +(a+b)x+ab$

Solution:-

51 × 41

= (50+1)(50-9)

$=50^2+50(-9+1)+(-9)(1)$

= 2500 + 50(-8) - 9

= 2500 - 400 - 9

= 2500 - 409

= 2091

Hence, 2091 is the solution.