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84\times 12x+123xx=350x
Multiply both sides of the equation by 7.
1008x+123xx=350x
Multiply 84 and 12 to get 1008.
1008x+123x^{2}=350x
Multiply x and x to get x^{2}.
1008x+123x^{2}-350x=0
Subtract 350x from both sides.
658x+123x^{2}=0
Combine 1008x and -350x to get 658x.
x\left(658+123x\right)=0
Factor out x.
x=0 x=-\frac{658}{123}
To find equation solutions, solve x=0 and 658+123x=0.
84\times 12x+123xx=350x
Multiply both sides of the equation by 7.
1008x+123xx=350x
Multiply 84 and 12 to get 1008.
1008x+123x^{2}=350x
Multiply x and x to get x^{2}.
1008x+123x^{2}-350x=0
Subtract 350x from both sides.
658x+123x^{2}=0
Combine 1008x and -350x to get 658x.
123x^{2}+658x=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{-658±\sqrt{658^{2}}}{2\times 123}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 123 for a, 658 for b, and 0 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-658±658}{2\times 123}
Take the square root of 658^{2}.
x=\frac{-658±658}{246}
Multiply 2 times 123.
x=\frac{0}{246}
Now solve the equation x=\frac{-658±658}{246} when ± is plus. Add -658 to 658.
x=0
Divide 0 by 246.
x=-\frac{1316}{246}
Now solve the equation x=\frac{-658±658}{246} when ± is minus. Subtract 658 from -658.
x=-\frac{658}{123}
Reduce the fraction \frac{-1316}{246} to lowest terms by extracting and canceling out 2.
x=0 x=-\frac{658}{123}
The equation is now solved.
84\times 12x+123xx=350x
Multiply both sides of the equation by 7.
1008x+123xx=350x
Multiply 84 and 12 to get 1008.
1008x+123x^{2}=350x
Multiply x and x to get x^{2}.
1008x+123x^{2}-350x=0
Subtract 350x from both sides.
658x+123x^{2}=0
Combine 1008x and -350x to get 658x.
123x^{2}+658x=0
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{123x^{2}+658x}{123}=\frac{0}{123}
Divide both sides by 123.
x^{2}+\frac{658}{123}x=\frac{0}{123}
Dividing by 123 undoes the multiplication by 123.
x^{2}+\frac{658}{123}x=0
Divide 0 by 123.
x^{2}+\frac{658}{123}x+\left(\frac{329}{123}\right)^{2}=\left(\frac{329}{123}\right)^{2}
Divide \frac{658}{123}, the coefficient of the x term, by 2 to get \frac{329}{123}. Then add the square of \frac{329}{123} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+\frac{658}{123}x+\frac{108241}{15129}=\frac{108241}{15129}
Square \frac{329}{123} by squaring both the numerator and the denominator of the fraction.
\left(x+\frac{329}{123}\right)^{2}=\frac{108241}{15129}
Factor x^{2}+\frac{658}{123}x+\frac{108241}{15129}. 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+\frac{329}{123}\right)^{2}}=\sqrt{\frac{108241}{15129}}
Take the square root of both sides of the equation.
x+\frac{329}{123}=\frac{329}{123} x+\frac{329}{123}=-\frac{329}{123}
Simplify.
x=0 x=-\frac{658}{123}
Subtract \frac{329}{123} from both sides of the equation.