(1)解方程:(x+1)(x-1)+2(x+3)=8.
(2)解方程:x2-8x+1=0.
(1)去括号得:x2-1+2x+6=8,
移项得:x2-1+2x+6-8=0,
合并同类项得:x2+2x-3=0,
(x+3)(x-1)=0,
x+3=0,x-1=0,
解得:x1=-3,x2=1.
(2)x2-8x=-1,
x2-8x+42=-1+42,
(x-4)2=15,
x-4=±
,15
x1=4+
,x2=4-15
.15
(1)解方程:(x+1)(x-1)+2(x+3)=8.
(2)解方程:x2-8x+1=0.
(1)去括号得:x2-1+2x+6=8,
移项得:x2-1+2x+6-8=0,
合并同类项得:x2+2x-3=0,
(x+3)(x-1)=0,
x+3=0,x-1=0,
解得:x1=-3,x2=1.
(2)x2-8x=-1,
x2-8x+42=-1+42,
(x-4)2=15,
x-4=±
,15
x1=4+
,x2=4-15
.15