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Hello, I need help solving this problem. Thank you so much

Hello, I need help solving this problem. Thank you so much-example-1

1 Answer

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(x)/(x+4)+(3)/(x+5)=(x+2)/(x^2+9x+20)

1. Factor the denominator of the expression on the irhgt of the equation:

- Write 9x as the sum of two terms that when you muliply the coefficient the result is 20:


x^2+9x+20=x^2+5x+4x+20

-Factor by parts: (common factor in frist two terms x and common factor in last two terms 4)


=x(x+5)+4(x+5)

-Factor (x+5)


=(x+5)(x+4)

Then, the given equation after the frist step is:


(x)/(x+4)+(3)/(x+5)=(x+2)/((x+5)(x+4))

2. Subtract the fraction on the right in both sides of the equation:


\begin{gathered} (x)/(x+4)+(3)/(x+5)-(x+2)/((x+5)(x+4))=(x+2)/((x+5)(x+4))-(x+2)/((x+5)(x+4)) \\ \\ (x)/(x+4)+(3)/(x+5)-(x+2)/((x+5)(x+4))=0 \end{gathered}

3. Write each fraction with LCD (x+5)(x+4)

-First fraction: multiply numerator and denominator by (x+5):


(x)/(x+4)\cdot(x+5)/(x+5)=(x(x+5))/((x+5)(x+4))

-Second fraction: multiply numerator and denominator by (x+4)


(3)/(x+5)\cdot(x+4)/(x+4)=(3(x+4))/((x+5)(x+4))

-Third fraction is written with the LCD.

Then, the expression written with LCD is:


(x(x+5))/((x+5)(x+4))+(3(x+4))/((x+5)(x+4))-(x+2)/((x+5)(x+4))=0

4. Solve the operartions of the fractions:


(x(x+5)+3(x+4)-(x+2))/((x+5)(x+4))=0

Simplify:


\begin{gathered} (x^2+5x+3x+12-x-2)/((x+5)(x+4))=0 \\ \\ (x^2+7x+10)/((x+5)(x+4))=0 \end{gathered}

5. Factor the numerator:

-Write 7x as the sum of two terms that when you muliply the coefficient the result is 10:


x^2+7x+10=x^2+5x+2x+10

-Factor by parts: (comon term in frist two terms is x, and comon factor in last two temrs is 2):


=x(x+5)+2(x+5)

-Factor (x+5):


=(x+5)(x+2)

Then, the equation after this step is:


((x+5)(x+2))/((x+5)(x+4))=0

6. Simplify:


(x+2)/(x+4)=0

7. Solve x:

When the quotient (result of division) is equal to 0, the numerator is equal to 0:


\begin{gathered} x+2=0 \\ \\ \text{Subtract 2 in both sides of the equation:} \\ x+2-2=0-2 \\ x=-2 \end{gathered}

Then, the solution for the given eqution is: x= -2

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