Question

设ab为有理数，且满足a+根号2b=（1-根号2）�0�5，求ab的值

Answer 1

a+根号2b=3-2根号2.因为a,b都为有理数，所以，根号2b=-2根号2.b=-2,a=3.ab=-6

Answer 2

a+根号2b=（1-根号2）�0�5=3-2根号2
所以a=3,b=-2 ab=-6

Answer 3

a=-2根号2
b=4.5
所以：ab=-9根号2

Answer 4

打开括号 则=3-2√2 则a=3 b=-2 ab=-6