Respuesta :

Answer:

  i) 75.8

  ii) 997,002

Step-by-step explanation:

Each of these expressions can be rewritten to make evaluation a little easier.

i)

The difference of squares can be factored.

  a^2 -b^2 = (a -b)(a +b)

  8.79^2 -1.21^2 = (8.79 -1.21)(8.79 +1.21) = (7.58)(10) = 75.8

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ii)

The values are near 1000, so can be expressed as differences from that number.

  (999)(998) = (1000 -1)(1000 -2) = 1000^2 -3(1000) +2) = 997,002