(1)x2+12x+25=0,
x2+12x=-25,
x2+12x+36=-25+36,
(x+6)2=11,
x+6=±
,
11
x1=
-6,x2=-
11
-6;
11
(2)x2+4x=10,
x2+4x+4=14,
(x+2)2=14,
x+2=±
,
14
x1=
-2,x2=-
14
-2;
14
(3)x2-6x=11,
x2-6x+9=20,
(x-3)2=20,
x-3=±2
,
5
x1=2
+3,x2=3-2
5
.
5
(1)
x²+12x+25=0
x²+12x+36=11
(x+6)²=11
x=-6+√11或x=-6-√11
(2)
x²+4x=10
x²+4x+4=14
(x+2)²=14
x=-2+√14或x=-2-√14
(3)
x²-6x=11
x²-6x+9=20
(x-3)²=20
x=3+2√5或x=3-2√5