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28x^{2}+121x^{2}=9
Multiply 2 and 14 to get 28.
149x^{2}=9
Combine 28x^{2} and 121x^{2} to get 149x^{2}.
x^{2}=\frac{9}{149}
Divide both sides by 149.
x=\frac{3\sqrt{149}}{149} x=-\frac{3\sqrt{149}}{149}
Take the square root of both sides of the equation.
28x^{2}+121x^{2}=9
Multiply 2 and 14 to get 28.
149x^{2}=9
Combine 28x^{2} and 121x^{2} to get 149x^{2}.
149x^{2}-9=0
Subtract 9 from both sides.
x=\frac{0±\sqrt{0^{2}-4\times 149\left(-9\right)}}{2\times 149}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 149 for a, 0 for b, and -9 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 149\left(-9\right)}}{2\times 149}
Square 0.
x=\frac{0±\sqrt{-596\left(-9\right)}}{2\times 149}
Multiply -4 times 149.
x=\frac{0±\sqrt{5364}}{2\times 149}
Multiply -596 times -9.
x=\frac{0±6\sqrt{149}}{2\times 149}
Take the square root of 5364.
x=\frac{0±6\sqrt{149}}{298}
Multiply 2 times 149.
x=\frac{3\sqrt{149}}{149}
Now solve the equation x=\frac{0±6\sqrt{149}}{298} when ± is plus.
x=-\frac{3\sqrt{149}}{149}
Now solve the equation x=\frac{0±6\sqrt{149}}{298} when ± is minus.
x=\frac{3\sqrt{149}}{149} x=-\frac{3\sqrt{149}}{149}
The equation is now solved.