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Solve for x (complex solution)
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\left(2x-400\right)\times 600-2x\times 600=x\left(x-200\right)
Variable x cannot be equal to any of the values 0,200 since division by zero is not defined. Multiply both sides of the equation by 2x\left(x-200\right), the least common multiple of x,x-200,2.
1200x-240000-2x\times 600=x\left(x-200\right)
Use the distributive property to multiply 2x-400 by 600.
1200x-240000-1200x=x\left(x-200\right)
Multiply 2 and 600 to get 1200.
1200x-240000-1200x=x^{2}-200x
Use the distributive property to multiply x by x-200.
1200x-240000-1200x-x^{2}=-200x
Subtract x^{2} from both sides.
1200x-240000-1200x-x^{2}+200x=0
Add 200x to both sides.
1400x-240000-1200x-x^{2}=0
Combine 1200x and 200x to get 1400x.
200x-240000-x^{2}=0
Combine 1400x and -1200x to get 200x.
-x^{2}+200x-240000=0
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.
x=\frac{-200±\sqrt{200^{2}-4\left(-1\right)\left(-240000\right)}}{2\left(-1\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -1 for a, 200 for b, and -240000 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-200±\sqrt{40000-4\left(-1\right)\left(-240000\right)}}{2\left(-1\right)}
Square 200.
x=\frac{-200±\sqrt{40000+4\left(-240000\right)}}{2\left(-1\right)}
Multiply -4 times -1.
x=\frac{-200±\sqrt{40000-960000}}{2\left(-1\right)}
Multiply 4 times -240000.
x=\frac{-200±\sqrt{-920000}}{2\left(-1\right)}
Add 40000 to -960000.
x=\frac{-200±200\sqrt{23}i}{2\left(-1\right)}
Take the square root of -920000.
x=\frac{-200±200\sqrt{23}i}{-2}
Multiply 2 times -1.
x=\frac{-200+200\sqrt{23}i}{-2}
Now solve the equation x=\frac{-200±200\sqrt{23}i}{-2} when ± is plus. Add -200 to 200i\sqrt{23}.
x=-100\sqrt{23}i+100
Divide -200+200i\sqrt{23} by -2.
x=\frac{-200\sqrt{23}i-200}{-2}
Now solve the equation x=\frac{-200±200\sqrt{23}i}{-2} when ± is minus. Subtract 200i\sqrt{23} from -200.
x=100+100\sqrt{23}i
Divide -200-200i\sqrt{23} by -2.
x=-100\sqrt{23}i+100 x=100+100\sqrt{23}i
The equation is now solved.
\left(2x-400\right)\times 600-2x\times 600=x\left(x-200\right)
Variable x cannot be equal to any of the values 0,200 since division by zero is not defined. Multiply both sides of the equation by 2x\left(x-200\right), the least common multiple of x,x-200,2.
1200x-240000-2x\times 600=x\left(x-200\right)
Use the distributive property to multiply 2x-400 by 600.
1200x-240000-1200x=x\left(x-200\right)
Multiply 2 and 600 to get 1200.
1200x-240000-1200x=x^{2}-200x
Use the distributive property to multiply x by x-200.
1200x-240000-1200x-x^{2}=-200x
Subtract x^{2} from both sides.
1200x-240000-1200x-x^{2}+200x=0
Add 200x to both sides.
1400x-240000-1200x-x^{2}=0
Combine 1200x and 200x to get 1400x.
1400x-1200x-x^{2}=240000
Add 240000 to both sides. Anything plus zero gives itself.
200x-x^{2}=240000
Combine 1400x and -1200x to get 200x.
-x^{2}+200x=240000
Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.
\frac{-x^{2}+200x}{-1}=\frac{240000}{-1}
Divide both sides by -1.
x^{2}+\frac{200}{-1}x=\frac{240000}{-1}
Dividing by -1 undoes the multiplication by -1.
x^{2}-200x=\frac{240000}{-1}
Divide 200 by -1.
x^{2}-200x=-240000
Divide 240000 by -1.
x^{2}-200x+\left(-100\right)^{2}=-240000+\left(-100\right)^{2}
Divide -200, the coefficient of the x term, by 2 to get -100. Then add the square of -100 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-200x+10000=-240000+10000
Square -100.
x^{2}-200x+10000=-230000
Add -240000 to 10000.
\left(x-100\right)^{2}=-230000
Factor x^{2}-200x+10000. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.
\sqrt{\left(x-100\right)^{2}}=\sqrt{-230000}
Take the square root of both sides of the equation.
x-100=100\sqrt{23}i x-100=-100\sqrt{23}i
Simplify.
x=100+100\sqrt{23}i x=-100\sqrt{23}i+100
Add 100 to both sides of the equation.