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

User Gauthier
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2 Answers

8 votes
8 votes

Answer:


\boxed{ \sf x=(4\pm√(43))/(2)}

Step-by-step explanation:


\rightarrow \sf (1)/(x-5)+(3)/(x+2)=4

make the denominators same


\rightarrow \sf (1(x+2))/((x-5)(x+2))+(3(x-5))/((x+2)(x-5))=4

join the fractions together


\rightarrow \sf (x+2+3x-15)/((x-5)(x+2))=4

cross multiply


\rightarrow \sf x+2+3x-15=4(x-5)(x+2)

simplify


\rightarrow \sf 4x-13=4x^2-12x-40

group the variables


\rightarrow \sf 4x^2-16x-27 = 0

use quadratic formula


\rightarrow \sf x = (-\left(-16\right)\pm √(\left(-16\right)^2-4\cdot \:4\left(-27\right)))/(2\cdot \:4)

simplify the following


\rightarrow \sf x=(4\pm√(43))/(2)

User Johann
by
2.5k points
22 votes
22 votes

Answer:


x=(4 \pm √(43))/(2)

Step-by-step explanation:

Given equation:


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

Make the denominators of the algebraic fractions the same, then combine them into one fraction:


\begin{aligned}\implies (1)/((x-5)) \cdot ((x+2))/((x+2))+(3)/((x+2))\cdot ((x-5))/((x-5)) & =4\\\\\implies (x+2)/((x-5)(x+2))+(3(x-5))/((x-5)(x+2)) & = 4\\\\ \implies (x+2+3(x-5))/((x-5)(x+2)) & = 4\\\\ \implies (4x-13)/((x-5)(x+2)) & = 4 \end{aligned}

Multiply both sides of the equation by
(x-5)(x+2):


\begin{aligned}\implies ((4x-13))/((x-5)(x+2))\cdot (x-5)(x+2) & = 4(x-5)(x+2)\\\\((4x-13)(x-5)(x+2))/((x-5)(x+2)) & = 4(x-5)(x+2)\\\\4x-13 & = 4(x-5)(x+2)\\\\4x-13 & =4x^2-12x-40\\\\4x^2-16x-27 & = 0\end{aligned}

Solve using the Quadratic Formula:


x=(-b \pm √(b^2-4ac) )/(2a)\quad\textsf{when}\:ax^2+bx+c=0


\implies a=4\\\implies b=-16\\\implies c=-27

Therefore:


\implies x=(-(-16) \pm √((-16)^2-4(4)(-27)) )/(2(4))


\implies x=(16 \pm √(688))/(8)


\implies x=(16 \pm 4 √(43))/(8)


\implies x=(4 \pm √(43))/(2)

User DhruvJoshi
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2.6k points