Solve for x
x = \frac{4 \sqrt{21}}{7} \approx 2.618614683
x = -\frac{4 \sqrt{21}}{7} \approx -2.618614683
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3x^{2}+4x^{2}=48
Multiply both sides of the equation by 48, the least common multiple of 16,12.
7x^{2}=48
Combine 3x^{2} and 4x^{2} to get 7x^{2}.
x^{2}=\frac{48}{7}
Divide both sides by 7.
x=\frac{4\sqrt{21}}{7} x=-\frac{4\sqrt{21}}{7}
Take the square root of both sides of the equation.
3x^{2}+4x^{2}=48
Multiply both sides of the equation by 48, the least common multiple of 16,12.
7x^{2}=48
Combine 3x^{2} and 4x^{2} to get 7x^{2}.
7x^{2}-48=0
Subtract 48 from both sides.
x=\frac{0±\sqrt{0^{2}-4\times 7\left(-48\right)}}{2\times 7}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 7 for a, 0 for b, and -48 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{0±\sqrt{-4\times 7\left(-48\right)}}{2\times 7}
Square 0.
x=\frac{0±\sqrt{-28\left(-48\right)}}{2\times 7}
Multiply -4 times 7.
x=\frac{0±\sqrt{1344}}{2\times 7}
Multiply -28 times -48.
x=\frac{0±8\sqrt{21}}{2\times 7}
Take the square root of 1344.
x=\frac{0±8\sqrt{21}}{14}
Multiply 2 times 7.
x=\frac{4\sqrt{21}}{7}
Now solve the equation x=\frac{0±8\sqrt{21}}{14} when ± is plus.
x=-\frac{4\sqrt{21}}{7}
Now solve the equation x=\frac{0±8\sqrt{21}}{14} when ± is minus.
x=\frac{4\sqrt{21}}{7} x=-\frac{4\sqrt{21}}{7}
The equation is now solved.
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