The answer is: 1323 . ______________________________________ Explanation: ______________________________________ If x + y = 10 ; then: x = 10 - y ; and y = 10 - x ;
If x - y = 4 ; then x = 4 + y ;
___________________________ Start with: "x + y = 10" ;
Substitute "(4+y)" for "x" ; ___________________________ (4+y) + y = 10 ; ___________________________ 4 + 2y = 10 ; subtract "4" from each side of the equation: _________________________________________ 4 + 2y - 4 = 10 - 4 ; _________________________________________ 2y = 6 ; divide each side of the equation by "2" ; to isolate "y" on one side of the equation; and to solve for "y"; _________________________________________ 2y/2= 6/2 ; ________________________________________ to get: y = 3 ; ________________________________________
Since: x + y = 10 ; substitute "3" for "y"; and solve for "x" : __________________________________________________ x + 3 = 10 ; subtract "3" from each side of the equation: ___________________________________________________ x + 3 - 3 = 10 - 3 ; ___________________________________________________ to get: x = 7 ; ____________________________________________________ Now, the question asks: what is: x² * y² ?
