Find all ordered pairs x, y of real numbers such that x+y=10 and x^2+y^2=64.
For example, to enter the solutions (2, 4) and (-3, 9), you would enter "(2,4),(-3,9)" (without the quotation marks).
To solve this, let's first isolate a.
(a+b)2=102
a2+2ab+b2=100
64+2ab=100
2ab=36
ab=18
b=10−a
a(10−a)=18
−a2+10a−18=0
a2−10a+18=0
Now, we can solve for a
a2−10a+25=7
(a−5)2=7
a−5=±√7
a=5±√7
We can now finally solve for b by plugging in each value of a.
a = (5 + sqrt(7)):
(5+√7)+b=10
b=5−√7
a = (5 - sqrt(7)):
(5−√7)+b=10
b=5+√7
Therefore, the solutions are (5 + sqrt(7), 5 - sqrt(7)) and (5 - sqrt(7), 5 + sqrt(7))