Use the interactive to find an expression equivalent to

Express into partial fractions 3x³ - 5x² - 3x - 40/( x² + 4)(x - 3)

Fudgin [204]

First simplify the rational expression by dividing. The degree in the numerator has to be at least 1 less than the degree in the denominator before you can decompose into partial fractions.

(3x³ - 5x² - 3x - 40) / ((x² + 4) (x - 3)) = 3 + (4x² - 15x - 4) / ((x² + 4) (x - 3))

Now decompose the remainder term into partial fractions:

(4x² - 15x - 4) / ((x² + 4) (x - 3)) = (ax + b) / (x² + 4) + c / (x - 3)

Multiply both sides by the denominator on the left:

4x² - 15x - 4 = (ax + b) (x - 3) + c (x² + 4)

Expand the right side:

4x² - 15x - 4 = ax² + (b - 3a) x - 3b + cx² + 4c

4x² - 15x - 4 = (a + c) x² + (b - 3a) x - 3b + 4c

Then

a + c = 4

b - 3a = -15

-3b + 4c = -4

Solve this system to get

a = 5, b = 0, c = -1

We end up with

(4x² - 15x - 4) / ((x² + 4) (x - 3)) = 5x / (x² + 4) - 1 / (x - 3)

and so

(3x³ - 5x² - 3x - 40) / ((x² + 4) (x - 3))

= 3 + 5x / (x² + 4) - 1 / (x - 3)

8 0

3 years ago

Preston bought a drum set priced at 187.90. The sales tax was found by multiplying the price of the drum set by 0.08. What was t

kobusy [5.1K]

Answer:

202.90

Step-by-step explanation:

If 187.90 is the price before the sales tax, you will multiply it by the 0.08 tax which will give you 15.032. You take 15.032 and add it to 187.90 because that is the sales tax. And after you add it and round to the nearest cent you get 202.90

7 0

3 years ago

I need help, this is geometry

Artemon [7]

Answer:

∠P = 39º

∠Q=120º

∠R = 21º

Step-by-step explanation:

m∠P+m∠Q+m∠R=180º (sum of ∠s in a triangle)

2x-3+6x-6+x=180º (substitution)

9x-9=180º (algebra)