Luana Utilize the tip #5 in the green box at the bottom of page 39. It states the following: A3 – B3 = (A – B)(A2 + AB + B2). Now look at the problem. The top is X3 – 27. This is the same as X3 –33. Letting X=A in the tip above and 3=B, we can say the following: X3 –33=(X – 3)( X2 + 3X + 32)= (X – 3)( X2 + 3X + 9) Notice that ( X2 + 3X + 9) is on the top and the bottom of the fraction, therefore it will cancel and what you will have left is (X – 3), which is the answer…
Ok on 17C. I don not understand how to factor out the 3X. I can get it...sort of to X-3 over 3X. But from there I am lost. Thanks.
ReplyDeleteLuana
ReplyDeleteUtilize the tip #5 in the green box at the bottom of page 39. It states the following:
A3 – B3 = (A – B)(A2 + AB + B2).
Now look at the problem. The top is X3 – 27. This is the same as X3 –33.
Letting X=A in the tip above and 3=B, we can say the following:
X3 –33=(X – 3)( X2 + 3X + 32)= (X – 3)( X2 + 3X + 9)
Notice that ( X2 + 3X + 9) is on the top and the bottom of the fraction, therefore it will cancel and what you will have left is (X – 3), which is the answer…
Hope this helps!
N S
YES!!!! Thank you
ReplyDelete