Subtract 4x^2 - x - 5 from product of x^2 + x + 3, x - 4

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igor_iv837

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Subtract 4x^2 -x-5 from the product of x^2 +x+3 and x-4

i multiplied (x^2 +x+3) (x-4)..... and then subtracted from 4x^2....... the answers doesnt come out right.... the answer book says x^3-7x^2-7
 
Re: Need help

The answer book is correct. Show all your work so we can identify your error.
 
Re: Need help

igor_iv837 said:
Subtract 4x^2 -x-5 from the product of x^2 +x+3 and x-4
i multiplied (x^2 +x+3) (x-4)..... and then subtracted from 4x^2....... the answers doesnt come out right.... the answer book says x^3-7x^2-7
Click to expand...
Let m = result of your multiplication; then subtraction does:
m - (4x^2 - x - 5)
= m - 4x^2 + x + 5 : is that the way you did it?
 
This is the way I did it guys....

Subtract 4x^2 -x-5 from the product of x^2 +x+3 and x-4


i multiplied (x^2 +x+3) (x-4)..... and then subtracted from 4x^2....... ......Is this equation right or not??? that's all i'm asking??? cuz it says 4x...subtract from the product of..x^2... and x-4 ....SO i wrote it like that (x^2 +x+3) (x-4)..... and then subtracted 4x^2 -x-5 from the answer of (x^2 +x+3) (x-4).....
 
igor_iv837 said:
This is the way I did it guys....

Subtract 4x^2 -x-5 from the product of x^2 +x+3 and x-4


i multiplied (x^2 +x+3) (x-4)..... and then subtracted from 4x^2....... ......Is this equation right or not??? that's all i'm asking??? cuz it says 4x...subtract from the product of..x^2... and x-4 ....SO i wrote it like that (x^2 +x+3) (x-4)..... and then subtracted 4x^2 -x-5 from the answer of (x^2 +x+3) (x-4).....
Click to expand...


Um, no.

Please carefully re-read the question. It says "subtract 4x^2 - x - 5 FROM the product of (x^2 + x + 3) and (x - 4).

Multiply (x^2 + x + 3)*(x - 4)


Then, subtract (4x^2 - x - 5) FROM that product.

In subtraction, it DOES make a difference which thing you subtract from which other thing.
 
Igor. How did you know that I am blind (refer to your sarcastic message to me)? You did not post your question in braille.
 
igor_iv837 said:
This is the way I did it ...

... subtracted from 4x^2 ...

... subtracted 4x^2 ... from ...
Click to expand...


You can't have it both ways.

Let's start with the first step. What did you get when you multiplied (x^2 + x + 3) times (x - 4)?

~ Mark :)
 
igor_iv837 said:
Subtract 4x^2 -x-5 from the product of x^2 +x+3 and x-4
Click to expand...
Igor, read that the same way as: Subtract 7 from the product of 9 and 5.
step1: 9 times 5 = 45
step2: 45 - 7 = 38
 
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