<p>Tell me what you guys think about this problem. I am not sure i agree with their answer, but i may be doing something wrong.</p>
<p>If n is an integer what is the remainder when 3x(2^(n+3))-4x(2^(n+2))+5x(2^(n+1))-8 is divided by x + 1?</p>
<p>a) -20
b) -10
c) -4
d) 0
e) The remainder cannot be determined</p>
<p>The answer/explanation given by the book is:
A: According to the Remainder Theorem, simply substitute -1 for x: 3(-1) - 4(1) + 5(-1) - 8 = -20.</p>
<p>Now that is great and all, but how could they ignore all of the 2^n's? if you assume n = 0 and solve from there you get
24x-16x+10x-8
reduces to...
18x - 8</p>
<p>divide that term by x+1 and the remainder is -26, NOT -20. Since -26 was not an answer choice I put E just because i had no clue *** was going on. is there something i'm missing? i have noticed several problems in both the barron's math and physics workbooks where they forgot to include key information in the problems (like leaving out the initial velocity of an object launched at 30 degrees when they want you to find it's maximum height), but i am just not sure about this one.</p>