x+y=39

xy=92

asked by guest
on Apr 04, 2025 at 3:58 am



You asked:

Solve the system of equations:x+y=39xy=92\begin{aligned}x + y &= 39\\x y &= 92\end{aligned}

MathBot Answer:

The system of equations has 22 solutions.

x=39211532,y=11532+392x = \frac{39}{2} - \frac{\sqrt{1153}}{2}, y = \frac{\sqrt{1153}}{2} + \frac{39}{2}x=11532+392,y=39211532x = \frac{\sqrt{1153}}{2} + \frac{39}{2}, y = \frac{39}{2} - \frac{\sqrt{1153}}{2}


Solve x+y=39x + y = 39 for xx. x=39yx = 39 - ySubstitute 39y39 - y for xx in xy=92x y = 92 and simplify. xy=92(39y)y=92y239y=92y239y+92=0y=(39)±(39)24(1)(92)2(39)y=39211532,y=11532+392\begin{aligned}x y &= 92 \\ \left(39 - y\right) y &= 92 \\ y^{2} - 39 y &= -92 \\y^{2} - 39 y + 92 &= 0 \\ y &= \frac{-(-39) \pm \sqrt{(-39)^{2} - 4(1)(92)}}{2(-39)} \\ y = \frac{39}{2} - \frac{\sqrt{1153}}{2}&, y = \frac{\sqrt{1153}}{2} + \frac{39}{2}\end{aligned}Substitute 39211532\frac{39}{2} - \frac{\sqrt{1153}}{2} into x+y=39x + y = 39 to solve for xx. x11532+392=39x+(39211532)=39x=11532+392\begin{aligned}x - \frac{\sqrt{1153}}{2} + \frac{39}{2} &= 39\\x + \left(\frac{39}{2} - \frac{\sqrt{1153}}{2}\right) &= 39\\x &= \frac{\sqrt{1153}}{2} + \frac{39}{2}\end{aligned}This yields the following solution. x=11532+392,y=39211532\begin{aligned}x = \frac{\sqrt{1153}}{2} + \frac{39}{2},\,y = \frac{39}{2} - \frac{\sqrt{1153}}{2}\end{aligned}Substitute 11532+392\frac{\sqrt{1153}}{2} + \frac{39}{2} into x+y=39x + y = 39 to solve for xx. x+11532+392=39x+(11532+392)=39x=39211532\begin{aligned}x + \frac{\sqrt{1153}}{2} + \frac{39}{2} &= 39\\x + \left(\frac{\sqrt{1153}}{2} + \frac{39}{2}\right) &= 39\\x &= \frac{39}{2} - \frac{\sqrt{1153}}{2}\end{aligned}This yields the following solution. x=39211532,y=11532+392\begin{aligned}x = \frac{39}{2} - \frac{\sqrt{1153}}{2},\,y = \frac{\sqrt{1153}}{2} + \frac{39}{2}\end{aligned}

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