We have:20+30+40+50+60+70+80

= ( 20 + 30 + 40 ) + (60 + 70 + 80) + 50

= 30 . 3 + 70 .3 + 50

= 100.3 + 50

= 300 + 50

= 350

We have:a³+b³+c³-3abc

=a³+3a²b+3ab²+b³+c³-3abc-3a²b-3ab²

=(a+b)³+c³-3ab(a+b+c)

=(a+b+c)[(a+b)²-(a+b).c+c²]-3ab(a+b+c)

=(a+b+c)(a²+b²+c²-ac-ab-bc)

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We have:g(-3)=2.(-3)+4=-6+4=-2

\(\Rightarrow\)f(g(-3))=f(-2)=(-2)²-2=4-2=2

Change:3 dozen oranges=36 oranges

The cost of a orange is:

90:4=22,5(cents)

The cost of 3 dozen oranges is:

 22,5 x 36=810(cents)

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