Question

设x、y是有理数,且x、y满足x²+2y+根号2×7=17-4倍根号2,求x+y的值.

Answer 1

x、y是有理数,满足x²+2y+（根号2）y=17－4乘根号2,

根据左右对应,所以有:

x^2+2y=17

y=-4

x^2=17-2y=25

得x=+5或=5

那么x+y=5-4=1或-5-4=-9