Question

用配方法将下列二次三项式化成a（x+h）²+k（a，h，k为已知数）的形式

①x²-6x+11；②3x²-6x-2；③-2x²-3x+1；④-2x²+5x-7

Answer 1

配方法其实很简单，只要你一步一步算，就会算对，不要省略步骤
例如②题，3、4题由于打字太慢了就不详解了，但是答案一定对，
前面两个回答的人算错了，最后祝你学习进步！
①x²-6x+11=(x-3)²-9+11=(x-3)²+2
②3x²-6x-2=3（x²-2x-2/3）=3[(x-1)²-1-2/3]=3[(x-1)²-5/3]=3(x-1)²-5
③-2x²-3x+1=-2(x+3/4)²+9/8+1=-2(x+3/4)²+17/8
④-2x²+5x-7=-2(x-5/4)²+25/8-7=-2(x-5/4)²-31/8

Answer 2

①x²-6x+11=(x-3)²-9+11=(x-3)²+2
②3x²-6x-2=3(x-1)²-3-2=3(x-1)²-5
③-2x²-3x+1=-2(x+3/4)²+9/2+1=-2(x+3/4)²+11/2
④-2x²+5x-7=-2(x-5/4)²+25/2-7=-2(x-5/4)²+11/2

Answer 3

1、原式=x^2-6x+9+2=（x-3）^2+2
2、原式=3（x^2-2x+1）-7=3（x-1）^2-7
3、原式=-2（x^2+3/2x+9/16）+17/8=-2（x+3/4）^2+17/8
4、原式=-2（x^2-5/2x+25/16）+31/8=-2（x-5/4）^2+31/8

Answer 4

1.=(x-3)^2+2
2.=3(x-1)^2-5
3.=-2(x+3/4)^2+17/8
4.=-2(x-5/4)^2-31/8

Answer 5

①x²-6x+11=(x-3)²+2
②3x²-6x-2=3(x²-2x-2/3)=3[(x-1)²-5/3]=3(x-1)²-5
③-2x²-3x+1=-2(x²+3/2x-1/2)=-2[(x+3/4)²-17/16]=-2(x+3/4)²+17/8
④-2x²+5x-7=-2(x²-5/2x+7/2)=-2[(x-5/4)²+31/16]=-2(x-5/4)²-31/8