Solve for x (complex solution)
x=-i\sqrt{\frac{15}{-4e^{2}+59}}\approx -0-0.713754534i
x=i\sqrt{\frac{15}{-4e^{2}+59}}\approx 0.713754534i
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15-4e^{2}x^{2}=25x^{2}+4\left(-21\right)x^{2}
Combine 4x^{2} and -25x^{2} to get -21x^{2}.
15-4e^{2}x^{2}=25x^{2}-84x^{2}
Multiply 4 and -21 to get -84.
15-4e^{2}x^{2}=-59x^{2}
Combine 25x^{2} and -84x^{2} to get -59x^{2}.
15-4e^{2}x^{2}+59x^{2}=0
Add 59x^{2} to both sides.
-4e^{2}x^{2}+59x^{2}=-15
Subtract 15 from both sides. Anything subtracted from zero gives its negation.
\left(-4e^{2}+59\right)x^{2}=-15
Combine all terms containing x.
x^{2}=-\frac{15}{-4e^{2}+59}
Dividing by -4e^{2}+59 undoes the multiplication by -4e^{2}+59.
x=\frac{15i}{\sqrt{-60e^{2}+885}} x=-\frac{15i}{\sqrt{-60e^{2}+885}}
Take the square root of both sides of the equation.
x=\frac{15i}{\sqrt{-60e^{2}+885}} x=\frac{-15i}{\sqrt{-60e^{2}+885}}
The equation is now solved.
15-4e^{2}x^{2}=25x^{2}+4\left(-21\right)x^{2}
Combine 4x^{2} and -25x^{2} to get -21x^{2}.
15-4e^{2}x^{2}=25x^{2}-84x^{2}
Multiply 4 and -21 to get -84.
15-4e^{2}x^{2}=-59x^{2}
Combine 25x^{2} and -84x^{2} to get -59x^{2}.
15-4e^{2}x^{2}+59x^{2}=0
Add 59x^{2} to both sides.
15+\left(-4e^{2}+59\right)x^{2}=0
Combine all terms containing x.
\left(-4e^{2}+59\right)x^{2}+15=0
Quadratic equations like this one, with an x^{2} term but no x term, can still be solved using the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, once they are put in standard form: ax^{2}+bx+c=0.
x=\frac{0±\sqrt{0^{2}-4\left(-4e^{2}+59\right)\times 15}}{2\left(-4e^{2}+59\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -4e^{2}+59 for a, 0 for b, and 15 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-4e^{2}+59\right)\times 15}}{2\left(-4e^{2}+59\right)}
Square 0.
x=\frac{0±\sqrt{\left(16e^{2}-236\right)\times 15}}{2\left(-4e^{2}+59\right)}
Multiply -4 times -4e^{2}+59.
x=\frac{0±\sqrt{240e^{2}-3540}}{2\left(-4e^{2}+59\right)}
Multiply 16e^{2}-236 times 15.
x=\frac{0±2i\sqrt{-60e^{2}+885}}{2\left(-4e^{2}+59\right)}
Take the square root of 240e^{2}-3540.
x=\frac{0±2i\sqrt{-60e^{2}+885}}{-8e^{2}+118}
Multiply 2 times -4e^{2}+59.
x=\frac{15i}{\sqrt{-60e^{2}+885}}
Now solve the equation x=\frac{0±2i\sqrt{-60e^{2}+885}}{-8e^{2}+118} when ± is plus.
x=\frac{-15i}{\sqrt{-60e^{2}+885}}
Now solve the equation x=\frac{0±2i\sqrt{-60e^{2}+885}}{-8e^{2}+118} when ± is minus.
x=\frac{15i}{\sqrt{-60e^{2}+885}} x=\frac{-15i}{\sqrt{-60e^{2}+885}}
The equation is now solved.
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