Question

今天快速完成,(1)x的平方+6x+y的平方-4y+13=0,则x=多少,y=多少(2)因式分解x的n+1的次方-2x的

Answer 1

1.原式化为：（X+3）2+(Y-2)2=0 X=-3 Y=2

2.Xn+1-2Xn+Xn-1 =Xn-1(X2-2X+1)=Xn-1(X-1)2(n+1 n-1 后面的2均为指数,下同)

3.X2+2XY+Y2-a(X+Y)+25=(X+Y)2-a(X+Y)+25

=(X+Y-5)2+10(X+Y)-a(X+Y)

a=10