(1)4y2-25=0, (2y+5)(2y-5)=0, 所以y1=-,y2=;
(2)(2x+3)2-36=0; (2x+3+6)(2x+3-6)=0, 所以x1=-,x2=;
(3)4(2x+5)2-1=0; [2(2x+5)+1][2(2x+5)-1]=0, 所以x1=-,x2=-;
(4)(x+)(x-)=7; x2-5=7, x2=12, 所以x1=-2,x2=2;
(5)x2+4x-1=0; ∵a=1,b=4,c=-1, ∴△=16-4×1×(-1)=20, ∴x==-2±, 所以x1=-2+,x2=-2-;
(6)x2-3x+2=0; (x-1)(x-2)=0, 所以x1=1,x2=2;
(7)2t2-7t-4=0; (t-4)(2t+1)=0, 所以t1=4,t2=-;
(8)(2x-1)2=(x-2)2. 2x-1=±(x-2), 即2x-1=x-2,或2x-1=-(x-2), 所以x1=-1,x2=1. |