因式分解【急死了,1.x²-4xy+4y²-10x+20y+252.(n+1)(n+2)(n+3)(n+4）+1填空题当x=_______时,代数式x²-4x+10有最小值,最小值是_______好的再加50分！
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因式分解【急死了,1.x²-4xy+4y²-10x+20y+252.(n+1)(n+2)(n+3)(n+4）+1填空题当x=_______时,代数式x²-4x+10有最小值,最小值是_______好的再加50分！
因式分解【急死了,
1.x²-4xy+4y²-10x+20y+25
2.(n+1)(n+2)(n+3)(n+4）+1
填空题
当x=_______时,代数式x²-4x+10有最小值,最小值是_______
好的再加50分！
因式分解【急死了,1.x²-4xy+4y²-10x+20y+252.(n+1)(n+2)(n+3)(n+4）+1填空题当x=_______时,代数式x²-4x+10有最小值,最小值是_______好的再加50分！
1.x²-4xy+4y²-10x+20y+25
=(x^2-4xy+4y^2)-(10x-20y)+25
=(x-2y)^2-10(x-2y)+25
=(x-2y-5)^2
2.(n+1)(n+2)(n+3)(n+4）+1
=[(n+1)(n+4)][(n+2)(n+3)]+1
=(n^2+5n+4)(n^2+5n+6)+1
=(n^2+5n)^2+10(n^2+5n)+24+1
=(n^2+5n)^2+10(n^2+5n)+25
=(n^2+5n+5)^2
填空题
当x=_______时,代数式x²-4x+10有最小值,最小值是_______
x^2-4x+10=(x^2-4x+4)+6
=(x-2)^2+6
因为(x-2)^2≥0
所以当(x-2)^2=0时,即x=2时,代数式x²-4x+10有最小值,最小值是6
1.x²-4xy+4y²-10x+20y+25
=(x-2y)^2-10(x-2y)+25
=(x-2y-5)^2
2.(n+1)(n+2)(n+3)(n+4）+1
=(n+1)(n+4)(n+2)(n+3)+1
=(n^2+5n+4)(n^2+5n+6)+1
=(n^2+5n)^2+10(n^2+5n)+25
=(n^2+5n+5)^2
第一题：
=(x-2y)^2-10(x-2y)+25
=「(x-2y)-5」^2
=(x-2y-5)^2
第二题：
{n+1}{n+2}{n+3}{n+4}+1
=[{n+1}{n+4}][{n+2}{n+3}]+1
=[{n^2+5n+4}][{n^2+5n+6}]+1
=[{n^2+5n+4}][{n^2+5n+4+2}]+1...
全部展开
第一题：
=(x-2y)^2-10(x-2y)+25
=「(x-2y)-5」^2
=(x-2y-5)^2
第二题：
{n+1}{n+2}{n+3}{n+4}+1
=[{n+1}{n+4}][{n+2}{n+3}]+1
=[{n^2+5n+4}][{n^2+5n+6}]+1
=[{n^2+5n+4}][{n^2+5n+4+2}]+1
=[{n^2+5n+4}]^2+2*[{n^2+5n+4}]*1+1
=[{n^2+5n+4}+1]^2
={n^2+5n+5}^2
填空题：
这个是二次函数问题
函数的对称轴是x=2
那么 当x=2时 代数式有最小值，最小值是：6
收起
1.x²-4xy+4y²-10x+20y+25
=(x-2y)^2-10(x-2y)+25
=(x-2y-5)^2
2.(n+1)(n+2)(n+3)(n+4）+1
=(n+1)(n+4)(n+2)(n+3)+1
=(n^2+5n+4)(n^2+5n+6)+1
=(n^2+5n)^2+10(n^2+5n)+25
=(n^2+5n+5)^2
填空题
当x=____2___时，代数式x²-4x+10有最小值，最小值是__6_____
填空
x^2-4X+10
=(x-2)^2+6
x=2时有最小值
1.x²-4xy+4y²-10x+20y+25
=(x-2y)^2-10(x-2y)+25
=(x-2y-5)^2
2.(n+1)(n+2)(n+3)(n+4）+1
=(n^2+5n+4)(n^2+5n+6)+1
=(n^2+5n)^2+10(n^2+5n)+24+1
=(n^2+5n+5)^2
当x=__2____时，代数式x²-4x+10有最小值，最小值是__6___
因为x²-4x+10=(x-2)^2+6