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Can anyone answer this question??

simplify using identities: I) (8.79)^2 - (1.21)^2
ii) 999 x 998
(algebraic expressions)

User Evan Nagle
by
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1 Answer

7 votes

Answer:

i) 75.8

ii) 997,002

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

User Ayush Singhal
by
3.4k points