Question

$$\frac{1}{x-7}-\frac{1}{x+4}=\frac{11}{30}$$

Answer

x=(3-sqrt(241))/2,(3+sqrt(241))/2

Solution


Multiply both sides by the Least Common Denominator: \(30(x-7)(x+4)\).
\[30(x+4)-30(x-7)=11(x-7)(x+4)\]
Simplify.
\[330=11{x}^{2}-33x-308\]
Move all terms to one side.
\[330-11{x}^{2}+33x+308=0\]
Simplify  \(330-11{x}^{2}+33x+308\)  to  \(638-11{x}^{2}+33x\).
\[638-11{x}^{2}+33x=0\]
Use the Quadratic Formula.
\[x=\frac{-33+11\sqrt{241}}{-22},\frac{-33-11\sqrt{241}}{-22}\]
Simplify solutions.
\[x=\frac{3-\sqrt{241}}{2},\frac{3+\sqrt{241}}{2}\]

Decimal Form: -6.262087, 9.262087