Find the remainder when x 3 + 4 x 2 − 5 x + 3 is divided by x − 2 .
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You can use synthetic division: Pardon my poor illustration, I can't figure out how to do this in latex: x − 2 becomes 2 and x 3 + 4 x 2 − 5 x + 3 becomes 1 4 -5 3.
Therefore, our answer is 1 7
x^3 + 4x^2 - 5x + 3 ÷ x-2 can be written as an identity as this form:
x^3 + 4x^2 - 5x + 3 = (x-2)(ax^2 + bx +c) +d (d being the remainder )
We can expand the second side out to get ax^3 + (b-2a)x^2 + (c-2b)x -2c +d
We can replace those values with the original equation so a=1, b-2a =4, c-2b=-5, -2c+d=3
We can rearrange and solve those to get a=1, b=6, c=7 and d=17, and since d is the remainder , the answer is 17
L e t P ( x ) = x 3 + 4 x 2 − 5 x + 3 T h e R e m a i n d e r T h e o r e m s t a t e s t h a t t h e r e m a i n d e r w h e n P ( x ) i s d i v i d e d b y x − a i s P ( a ) U s i n g t h e r e m a i n d e r t h e o r e m , T h e r e m a i n d e r w h e n d i v i d i n g P ( x ) b y x − 2 i s P ( 2 ) = 8 + 1 6 − 1 0 + 3 = 2 4 − 7 = 1 7 P ( 2 ) = 1 7
put x-2=0 or x=2 in given equation x^3 + 4 x^2 -5 x +3 and we get 17 that will be the reminder
I believe you are using the remainder theorem. Let me help you organise your solution.
P ( x ) = x 3 + 4 x 2 − 5 x + 3
By Remainder Theorem,
P ( 2 ) = 8 + 4 ( 2 ) 2 − 5 ( 2 ) + 3 = 1 7
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Boon how you know
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boon what is mod i dont really understand its purpose
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Let f ( x ) = x 3 + 4 x 2 − 5 x + 3 and r = R e m a i n d e r
x − 2 = 0 ⇒ x = 2
Due to the remainder theorem f ( x ) = r so when x = 2
f ( 2 ) = r
Substituting f ( x ) = x 3 + 4 x 2 − 5 x + 3 gives us
( 2 ) 3 + 4 ( 2 ) 2 − 5 ( 2 ) + 3 = r
This expands out into
8 + 1 6 − 1 0 + 3 = r
Evaluating this (using Bidmas of course) gives us
1 7 = r
So the remainder is 1 7