12 13x x videos俄罗斯:x方+(5-x)方=13

把方程展开得x^2+25+x^2-10x=13

2x^2-10x+12=0

解得x=3或2

x^2+X^2-10x+25=13

2x^2-10x+12=0

x^2-5x+6=0

(x-2)(x-3)=0

X1=2 X2=3

X^2+(5-X^2)=13

解：X^2+25-10X+X^2-13=0

2X^2-10X+12=0

X^2-5X+6=0

(X-2)(X-3)=0

解得：X1=212 13x x videos俄罗斯，X2=3