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25x^{2}-16y^{2}=400
Consider the first equation. Multiply both sides of the equation by 400, the least common multiple of 16,25.
125x-48y=481,-16y^{2}+25x^{2}=400
To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.
125x-48y=481
Solve 125x-48y=481 for x by isolating x on the left hand side of the equal sign.
125x=48y+481
Subtract -48y from both sides of the equation.
x=\frac{48}{125}y+\frac{481}{125}
Divide both sides by 125.
-16y^{2}+25\left(\frac{48}{125}y+\frac{481}{125}\right)^{2}=400
Substitute \frac{48}{125}y+\frac{481}{125} for x in the other equation, -16y^{2}+25x^{2}=400.
-16y^{2}+25\left(\frac{2304}{15625}y^{2}+\frac{46176}{15625}y+\frac{231361}{15625}\right)=400
Square \frac{48}{125}y+\frac{481}{125}.
-16y^{2}+\frac{2304}{625}y^{2}+\frac{46176}{625}y+\frac{231361}{625}=400
Multiply 25 times \frac{2304}{15625}y^{2}+\frac{46176}{15625}y+\frac{231361}{15625}.
-\frac{7696}{625}y^{2}+\frac{46176}{625}y+\frac{231361}{625}=400
Add -16y^{2} to \frac{2304}{625}y^{2}.
-\frac{7696}{625}y^{2}+\frac{46176}{625}y-\frac{18639}{625}=0
Subtract 400 from both sides of the equation.
y=\frac{-\frac{46176}{625}±\sqrt{\left(\frac{46176}{625}\right)^{2}-4\left(-\frac{7696}{625}\right)\left(-\frac{18639}{625}\right)}}{2\left(-\frac{7696}{625}\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -16+25\times \left(\frac{48}{125}\right)^{2} for a, 25\times \frac{481}{125}\times \frac{48}{125}\times 2 for b, and -\frac{18639}{625} for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
y=\frac{-\frac{46176}{625}±\sqrt{\frac{2132222976}{390625}-4\left(-\frac{7696}{625}\right)\left(-\frac{18639}{625}\right)}}{2\left(-\frac{7696}{625}\right)}
Square 25\times \frac{481}{125}\times \frac{48}{125}\times 2.
y=\frac{-\frac{46176}{625}±\sqrt{\frac{2132222976}{390625}+\frac{30784}{625}\left(-\frac{18639}{625}\right)}}{2\left(-\frac{7696}{625}\right)}
Multiply -4 times -16+25\times \left(\frac{48}{125}\right)^{2}.
y=\frac{-\frac{46176}{625}±\sqrt{\frac{2132222976-573782976}{390625}}}{2\left(-\frac{7696}{625}\right)}
Multiply \frac{30784}{625} times -\frac{18639}{625} by multiplying numerator times numerator and denominator times denominator. Then reduce the fraction to lowest terms if possible.
y=\frac{-\frac{46176}{625}±\sqrt{\frac{2493504}{625}}}{2\left(-\frac{7696}{625}\right)}
Add \frac{2132222976}{390625} to -\frac{573782976}{390625} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
y=\frac{-\frac{46176}{625}±\frac{72\sqrt{481}}{25}}{2\left(-\frac{7696}{625}\right)}
Take the square root of \frac{2493504}{625}.
y=\frac{-\frac{46176}{625}±\frac{72\sqrt{481}}{25}}{-\frac{15392}{625}}
Multiply 2 times -16+25\times \left(\frac{48}{125}\right)^{2}.
y=\frac{\frac{72\sqrt{481}}{25}-\frac{46176}{625}}{-\frac{15392}{625}}
Now solve the equation y=\frac{-\frac{46176}{625}±\frac{72\sqrt{481}}{25}}{-\frac{15392}{625}} when ± is plus. Add -\frac{46176}{625} to \frac{72\sqrt{481}}{25}.
y=-\frac{225\sqrt{481}}{1924}+3
Divide -\frac{46176}{625}+\frac{72\sqrt{481}}{25} by -\frac{15392}{625} by multiplying -\frac{46176}{625}+\frac{72\sqrt{481}}{25} by the reciprocal of -\frac{15392}{625}.
y=\frac{-\frac{72\sqrt{481}}{25}-\frac{46176}{625}}{-\frac{15392}{625}}
Now solve the equation y=\frac{-\frac{46176}{625}±\frac{72\sqrt{481}}{25}}{-\frac{15392}{625}} when ± is minus. Subtract \frac{72\sqrt{481}}{25} from -\frac{46176}{625}.
y=\frac{225\sqrt{481}}{1924}+3
Divide -\frac{46176}{625}-\frac{72\sqrt{481}}{25} by -\frac{15392}{625} by multiplying -\frac{46176}{625}-\frac{72\sqrt{481}}{25} by the reciprocal of -\frac{15392}{625}.
x=\frac{48}{125}\left(-\frac{225\sqrt{481}}{1924}+3\right)+\frac{481}{125}
There are two solutions for y: 3-\frac{225\sqrt{481}}{1924} and 3+\frac{225\sqrt{481}}{1924}. Substitute 3-\frac{225\sqrt{481}}{1924} for y in the equation x=\frac{48}{125}y+\frac{481}{125} to find the corresponding solution for x that satisfies both equations.
x=\frac{48\left(-\frac{225\sqrt{481}}{1924}+3\right)+481}{125}
Multiply \frac{48}{125} times 3-\frac{225\sqrt{481}}{1924}.
x=\frac{48}{125}\left(\frac{225\sqrt{481}}{1924}+3\right)+\frac{481}{125}
Now substitute 3+\frac{225\sqrt{481}}{1924} for y in the equation x=\frac{48}{125}y+\frac{481}{125} and solve to find the corresponding solution for x that satisfies both equations.
x=\frac{48\left(\frac{225\sqrt{481}}{1924}+3\right)+481}{125}
Multiply \frac{48}{125} times 3+\frac{225\sqrt{481}}{1924}.
x=\frac{48\left(-\frac{225\sqrt{481}}{1924}+3\right)+481}{125},y=-\frac{225\sqrt{481}}{1924}+3\text{ or }x=\frac{48\left(\frac{225\sqrt{481}}{1924}+3\right)+481}{125},y=\frac{225\sqrt{481}}{1924}+3
The system is now solved.