Question

若x、y为实数,且满足根号x-1+(3x+y-1)的平方=0,求根号下5x+y平方

Answer 1

√X-1+(3X+Y-1)^2=0

因为

√X-1>=0,

(3X+Y-1)^2>=0

而

√X-1+(3X+Y-1)^2=0

所以

x-1=0(1)

3x+y-1=0(2)

由(1)(2)得x=1,y=-2

√5X+Y^2=√5*1+(-2)^2=√5+4