The polinomial f(x) divided x-3 results in a quotient of x^2+3x-5 and reminder of two. Find f(3).

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hala718's profile pic

hala718 | High School Teacher | (Level 1) Educator Emeritus

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Given that the quotient of dividing f(x) by (x-3) , the results will be x^2 + 3x -5  and remainder of 2:

Then f(x) is a product of two functions, including (x-3), plus two.

==> f(x) = (x-3)*R(x) + 2

Let us write :

f(x) / (x-3) = (x^+ 3x -5) + 2

We will multiply by (x-3).

==> f(x) = (x-3)(x^2 +3x -5) + 2

Now to find f(3) we will substitute with x= 3 :

f(3) = (3-3)( 3^2 + 3&3 -5) + 2

==> f(3) = 0 + 2 = 2

Then, we know that:

f(3) = 2

 

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neela | High School Teacher | (Level 3) Valedictorian

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By division algorithm if a/ b = q and remainder is r, then a = bq+r.

Given that the f(x)/(x-2) = x^2+3x-5 is the quotient  and remainder is 2.

Therefore f(x) = (x-3)(x^2+3x-5) +2.

So to find the value of f(3), we just  put x= 3 in  f(x) = (x-3)(x^2+3x-5).

Therefore f(3) = (3-3){3^2+3*3-5} +2

f(3) = (0){....}+2

f(3) = 2.

Therefore f(3) = 2.

 

giorgiana1976's profile pic

giorgiana1976 | College Teacher | (Level 3) Valedictorian

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To determine f(3), first we need to find out the expression of f(x). Since the quotient is of 2nd order and the divisor is of 1st order, then the order of f(x) is :

f(x)'s order = quotient's order + divisor's order

f(x)'s order = 2 + 1

f(x)'s order = 3 order

We'll write the rule of division with reminder:

f(x) = quotient *Divisor + remainder

f(x)= (x^2 +3x-5)(x-3) + 2

We'll substitute x by 3:

f(3) = (9 + 9 - 5)(3 - 3) + 2

f(3) = 2

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