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Solve for x (complex solution)
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7\times 8+8\times 7xx=xx
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by x.
7\times 8+8\times 7x^{2}=xx
Multiply x and x to get x^{2}.
7\times 8+8\times 7x^{2}=x^{2}
Multiply x and x to get x^{2}.
56+56x^{2}=x^{2}
Multiply 7 and 8 to get 56. Multiply 8 and 7 to get 56.
56+56x^{2}-x^{2}=0
Subtract x^{2} from both sides.
56+55x^{2}=0
Combine 56x^{2} and -x^{2} to get 55x^{2}.
55x^{2}=-56
Subtract 56 from both sides. Anything subtracted from zero gives its negation.
x^{2}=-\frac{56}{55}
Divide both sides by 55.
x=\frac{2\sqrt{770}i}{55} x=-\frac{2\sqrt{770}i}{55}
The equation is now solved.
7\times 8+8\times 7xx=xx
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by x.
7\times 8+8\times 7x^{2}=xx
Multiply x and x to get x^{2}.
7\times 8+8\times 7x^{2}=x^{2}
Multiply x and x to get x^{2}.
56+56x^{2}=x^{2}
Multiply 7 and 8 to get 56. Multiply 8 and 7 to get 56.
56+56x^{2}-x^{2}=0
Subtract x^{2} from both sides.
56+55x^{2}=0
Combine 56x^{2} and -x^{2} to get 55x^{2}.
55x^{2}+56=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\times 55\times 56}}{2\times 55}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 55 for a, 0 for b, and 56 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 55\times 56}}{2\times 55}
Square 0.
x=\frac{0±\sqrt{-220\times 56}}{2\times 55}
Multiply -4 times 55.
x=\frac{0±\sqrt{-12320}}{2\times 55}
Multiply -220 times 56.
x=\frac{0±4\sqrt{770}i}{2\times 55}
Take the square root of -12320.
x=\frac{0±4\sqrt{770}i}{110}
Multiply 2 times 55.
x=\frac{2\sqrt{770}i}{55}
Now solve the equation x=\frac{0±4\sqrt{770}i}{110} when ± is plus.
x=-\frac{2\sqrt{770}i}{55}
Now solve the equation x=\frac{0±4\sqrt{770}i}{110} when ± is minus.
x=\frac{2\sqrt{770}i}{55} x=-\frac{2\sqrt{770}i}{55}
The equation is now solved.