Math  /  Algebra

Questionf(x)=2x25x3g(x)=2x2+5x+2\begin{array}{l} f(x)=2 x^{2}-5 x-3 \\ g(x)=2 x^{2}+5 x+2 \end{array}
Find: (fg)(x)\left(\frac{f}{g}\right)(x) x+3x+2\frac{x+3}{x+2} x3x+2\frac{x-3}{x+2} x21x32x^{2}-1 x-\frac{3}{2} 2x25x32x2+5x+2\frac{2 x^{2}-5 x-3}{2 x^{2}+5 x+2}

Studdy Solution

STEP 1

What is this asking? We're asked to divide the function f(x)f(x) by the function g(x)g(x), creating a brand new function! Watch out! Don't forget to factor and simplify whenever possible.
Sometimes, things magically disappear!

STEP 2

1. Define the functions
2. Divide *f(x)* by *g(x)*
3. Factor the numerator
4. Factor the denominator
5. Simplify the expression

STEP 3

We're given two fantastic functions, f(x)f(x) and g(x)g(x).
Let's write them down clearly: f(x)=2x25x3f(x) = 2x^2 - 5x - 3 g(x)=2x2+5x+2g(x) = 2x^2 + 5x + 2This is our starting point.
Woohoo!

STEP 4

Now, let's create our new function, which is f(x)g(x)\frac{f(x)}{g(x)}.
It's as simple as putting f(x)f(x) on top and g(x)g(x) on the bottom.
Like a mathematical sandwich! f(x)g(x)=2x25x32x2+5x+2\frac{f(x)}{g(x)} = \frac{2x^2 - 5x - 3}{2x^2 + 5x + 2}

STEP 5

Let's factor the top part of our fraction, the **numerator**.
We're looking for two numbers that multiply to (23)=6(2 \cdot -3) = \mathbf{-6} and add up to 5\mathbf{-5}.
Those magical numbers are 6\mathbf{-6} and 1\mathbf{1}.

STEP 6

Rewriting our numerator, we get: 2x26x+1x32x^2 - 6x + 1x - 3

STEP 7

Now, we can factor by grouping: 2x(x3)+1(x3)2x(x - 3) + 1(x - 3) (2x+1)(x3)(2x + 1)(x - 3)Look at that, factored!

STEP 8

Time to factor the bottom part of our fraction, the **denominator**.
We need two numbers that multiply to (22)=4(2 \cdot 2) = \mathbf{4} and add up to 5\mathbf{5}.
Those numbers are 4\mathbf{4} and 1\mathbf{1}.

STEP 9

Rewriting our denominator, we get: 2x2+4x+1x+22x^2 + 4x + 1x + 2

STEP 10

Factoring by grouping gives us: 2x(x+2)+1(x+2)2x(x + 2) + 1(x + 2) (2x+1)(x+2)(2x + 1)(x + 2)Boom! Factored!

STEP 11

Now, let's put our factored numerator and denominator back into the fraction: (2x+1)(x3)(2x+1)(x+2)\frac{(2x + 1)(x - 3)}{(2x + 1)(x + 2)}

STEP 12

Notice that (2x+1)(2x + 1) appears on both the top and the bottom.
We can divide both by (2x+1)(2x+1) to simplify!
We're essentially multiplying by 1/(2x+1)1/(2x+1)\frac{1/(2x+1)}{1/(2x+1)}, which is the same as multiplying by one! (2x+1)(x3)(2x+1)(x+2)1/(2x+1)1/(2x+1)=x3x+2\frac{(2x + 1)(x - 3)}{(2x + 1)(x + 2)} \cdot \frac{1/(2x+1)}{1/(2x+1)} = \frac{x-3}{x+2}

STEP 13

Our final simplified function is x3x+2\frac{x-3}{x+2}.
Fantastic!

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