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-28x^{2}+4=0
Combine 9x^{2} and -37x^{2} to get -28x^{2}.
-28x^{2}=-4
Subtract 4 from both sides. Anything subtracted from zero gives its negation.
x^{2}=\frac{-4}{-28}
Divide both sides by -28.
x^{2}=\frac{1}{7}
Reduce the fraction \frac{-4}{-28} to lowest terms by extracting and canceling out -4.
x=\frac{\sqrt{7}}{7} x=-\frac{\sqrt{7}}{7}
Take the square root of both sides of the equation.
-28x^{2}+4=0
Combine 9x^{2} and -37x^{2} to get -28x^{2}.
x=\frac{0±\sqrt{0^{2}-4\left(-28\right)\times 4}}{2\left(-28\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -28 for a, 0 for b, and 4 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\left(-28\right)\times 4}}{2\left(-28\right)}
Square 0.
x=\frac{0±\sqrt{112\times 4}}{2\left(-28\right)}
Multiply -4 times -28.
x=\frac{0±\sqrt{448}}{2\left(-28\right)}
Multiply 112 times 4.
x=\frac{0±8\sqrt{7}}{2\left(-28\right)}
Take the square root of 448.
x=\frac{0±8\sqrt{7}}{-56}
Multiply 2 times -28.
x=-\frac{\sqrt{7}}{7}
Now solve the equation x=\frac{0±8\sqrt{7}}{-56} when ± is plus.
x=\frac{\sqrt{7}}{7}
Now solve the equation x=\frac{0±8\sqrt{7}}{-56} when ± is minus.
x=-\frac{\sqrt{7}}{7} x=\frac{\sqrt{7}}{7}
The equation is now solved.