因式分解:x^2-4(2y-5)x+4(2y-5)^2+2x-8y+21

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因式分解:x^2-4(2y-5)x+4(2y-5)^2+2x-8y+21

因式分解:x^2-4(2y-5)x+4(2y-5)^2+2x-8y+21
因式分解:x^2-4(2y-5)x+4(2y-5)^2+2x-8y+21

因式分解:x^2-4(2y-5)x+4(2y-5)^2+2x-8y+21
设2y-5=t
x^2-4tx+4t^2+2x-4(2y-5)-20+21
=x^2-4tx+4t^2+2x-4t+1
=x^2-(4t-2)x+4t^2-4t+1
=x^2-2(2t-1)x+(2t-1)^2
=(x-2t+1)^2
=(x-2(2y-5)+1)^2
=(x-4y+11)^2

原式=[x-2(2y-5)]²+2x-8y+21
=(x-4y+10)²+2(x-4y+10)+1
=(x-4y+10+1)²
=(x-4y+11)²16(x^2+4x+4)^2(x^2-2x+1)-(x^2-6x+9)^2原式=[4(x+2)(x-1)]²-(x²-6x+9)² =(4x²+...

全部展开

原式=[x-2(2y-5)]²+2x-8y+21
=(x-4y+10)²+2(x-4y+10)+1
=(x-4y+10+1)²
=(x-4y+11)²

收起

x^2-4(2y-5)x+4(2y-5)^2+2x-8y+21
=(x-2(2y-5)}^2+2(x-4y+10)+1
=(x-4y+10)^2+2(x-4y+10)+1
=(x-4y+10+1)^2
=(x-4y+11)^2

x^2+16y^2-8xy+22x-88y+121

先展开,再合并啊

(x+11)~2+16(y-0.5)~2-4