x^2=9分之1 x^2-36=0 4X^2=49 2分之1x^2-4=0
(1)x=±3åä¹1
(2)x^2=36
x=±6
(3)x^2=4åä¹49
x=±2åä¹7
(4)x^2=8
x=±2Â·æ ¹å·2