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Solve for x (complex solution)
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3\times 5=-xx
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 3x, the least common multiple of x,3.
3\times 5=-x^{2}
Multiply x and x to get x^{2}.
15=-x^{2}
Multiply 3 and 5 to get 15.
-x^{2}=15
Swap sides so that all variable terms are on the left hand side.
x^{2}=-15
Divide both sides by -1.
x=\sqrt{15}i x=-\sqrt{15}i
The equation is now solved.
3\times 5=-xx
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 3x, the least common multiple of x,3.
3\times 5=-x^{2}
Multiply x and x to get x^{2}.
15=-x^{2}
Multiply 3 and 5 to get 15.
-x^{2}=15
Swap sides so that all variable terms are on the left hand side.
-x^{2}-15=0
Subtract 15 from both sides.
x=\frac{0±\sqrt{0^{2}-4\left(-1\right)\left(-15\right)}}{2\left(-1\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -1 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(-1\right)\left(-15\right)}}{2\left(-1\right)}
Square 0.
x=\frac{0±\sqrt{4\left(-15\right)}}{2\left(-1\right)}
Multiply -4 times -1.
x=\frac{0±\sqrt{-60}}{2\left(-1\right)}
Multiply 4 times -15.
x=\frac{0±2\sqrt{15}i}{2\left(-1\right)}
Take the square root of -60.
x=\frac{0±2\sqrt{15}i}{-2}
Multiply 2 times -1.
x=-\sqrt{15}i
Now solve the equation x=\frac{0±2\sqrt{15}i}{-2} when ± is plus.
x=\sqrt{15}i
Now solve the equation x=\frac{0±2\sqrt{15}i}{-2} when ± is minus.
x=-\sqrt{15}i x=\sqrt{15}i
The equation is now solved.