Question

若|3x-y-1|和√2x+y-4互为相反数,求x+4y的算术平方根

Answer 1

|3x-y-1|和√2x+y-4互为相反数
根号平方大于等于0
所以只有0的相反数是0
所以3x-y-1=0 ;2x+y-4=0
解得x=1 ,y=2
x+4y的算术平方根3

Answer 2

∵|3x-y-1|和√2x+y-4都≥0
又|3x-y-1|和√2x+y-4互为相反数
∴3x-y-1=0 2x+y-4=0
解得x=1 y=2

x+4y=9

算术平方根为3