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avatar+777 

for this question first i identified (r+1)^2 = r^2+2r+1

i subbed in r+1 into r which gave me f(r+1)= 2r^3 + 8r^2 + 13r + 6 

then subtracted the expanded version of f(r) which is 2r^3 + 3r^2 + r

which at the end gave me 5r^2 + 12r + 6

i think the 5 in my answer should be 6 

spot my mistake please.

 Dec 29, 2018
 #1
avatar+17163 
+3

You are correct in your assumption.....

instead of  2 r^3 + 8r^2 + 13 r + 6      I get

                  2 r^3 + 9r^2 + 13r + 6  .......     So when you were expanding, you got something a little befuzzled.....look at it again....G'Luck ! cheeky

 Dec 29, 2018
 #2
avatar+777 
+1

WOW i did 3r^2 + 6r^2 = 8r^2 LOL

thank you so much, i looked at it for about 3 times before posting as well... angry

YEEEEEET  Dec 29, 2018

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