若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y=

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若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y=若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y=若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×

若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y=
若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y=

若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y=
你把X*X+Y*Y看成一个未知数,比如是t,t>=0
原题就是t(t-5)=36
所以是9,舍去了-4这个值

m=x*x+y*y
m*(m-5)=36
m^2-5m-36=0
(m-9)*(m+4)=0
m1=9
m2=-4