Question

using property 401^2-399^2​

Answer 1

Step-by-step explanation:

[400+1]²-[400-1]²

a²-b²=[a+b]a-b

[400+1+400-1][400+1-{400-1}]

[800][400-400+1+1]

[800][2]

1600

hope it helps you

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