Question

I have the answer, 2-(3/x+2)

Answer 1

Answer:

a = 2

b = -3

Step-by-step explanation:

the secret is seeing that the numerator (top part of the division) contains 2x. that means 2 times the factor of x in the denominator (bottom part of the division).

so, we want to change the numerator that we can simply say the result is 2 and some rest (remainder).

2×(x+2) would be 2x + 4

aha !

and we have 2x+1 up there. so, what had to happen to get from 2x+4 to 2x+1 ? we had to subtract 3. it to get to 2x+4 we have to add 3.

but if we add 3, we need also to subtract 3 to keep the value of the whole expression the same.

therefore we get

(2x+1)/(x+2) = (2x+4)/(x+2) - 3/(x+2) =

= 2×(x+2)/(x+2) - 3/(x+2) = 2 - 3/(x+2)

Answer 2

Start with the answer format we want, and work your way toward forming a single fraction like so

$a + \frac{b}{x+2}\\\\a*1+\frac{b}{x+2}\\\\a*\frac{x+2}{x+2}+\frac{b}{x+2}\\\\\frac{a(x+2)}{x+2}+\frac{b}{x+2}\\\\\frac{a(x+2)+b}{x+2}\\\\\frac{ax+2a+b}{x+2}\\\\\frac{ax+(2a+b)}{x+2}$

Compare that last expression to (2x+1)/(x+2). Notice how the ax and 2x match up, so a = 2 must be the case.

Then we have 2a+b as the remaining portion in the numerator. Plugging in a = 2 leads to 2a+b = 2*2+b = 4+b. Set this equal to the +1 found in (2x+1)/(x+2) to have the terms match.

So, 4+b = 1 leads to b = -3

Therefore, a = 2 and b = -3

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An alternative route:

$\frac{2x+1}{x+2}\\\\\frac{2x+1+0}{x+2}\\\\\frac{2x+1+4-4}{x+2}\\\\\frac{(2x+4)+1-4}{x+2}\\\\\frac{2(x+2)-3}{x+2}\\\\\frac{2(x+2)}{x+2}+\frac{-3}{x+2}\\\\2-\frac{3}{x+2}$

I added and subtracted 4 in the third step so that I could form 2x+4, which then factors to 2(x+2). That way I could cancel out a pair of (x+2) terms toward the very end.

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Other alternative methods involve synthetic division or polynomial long division. They are slightly separate but related concepts.