Question

(b) Using the formula (a-b)2 = a2 – 2ab + b2

Evaluate: (389)2

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Answer 1

Answer:

151321

Step-by-step explanation:

we have check the nearest to 100s that is 400.if we subtract 11 from 400 then (400-11)^2 becomes the perfect pair..then only apply the formula.

Answer 2

Answer:

$(389) {}^{2} = (400 - 11) {}^{2 } \\ formula \\ (a - b) {}^{2} = a {}^{2} - 2ab + b {}^{2} \\ (400 - 11) {}^{2} = (400) {}^{2} - 2(400)(11) + (11) {}^{2} \\ = 160000 - 8800 + 121 \\ = 151321$