这道题怎么算(x-8)(-10x+300)
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这道题怎么算(x-8)(-10x+300)
(x-8)(-10x+300) 是怎么算的 =-10(x-8)(x-30) =-10(x2-38x+240) =-10(x-19)2+1210
(x-8)(-10x+300) 是怎么算的 =-10(x-8)(x-30) =-10(x2-38x+240) =-10(x-19)2+1210
![这道题怎么算(x-8)(-10x+300)](/uploads/image/z/16006175-71-5.jpg?t=%E8%BF%99%E9%81%93%E9%A2%98%E6%80%8E%E4%B9%88%E7%AE%97%28x-8%29%28-10x%EF%BC%8B300%29)
(x-8)(-10x+300)
=(x-8)[-10(x-30)]
= -10(x-8)(x-30)
=-10[x(x-30)-8(x-30)]
=-10(x2-30x-8x+240)
=-10(x2-38x+240)
=-10[(x2-19*2x+19*19)-19*19+240]
=-10[(x-19)2-361+240]
=-10(x-19)2-1210
=(x-8)[-10(x-30)]
= -10(x-8)(x-30)
=-10[x(x-30)-8(x-30)]
=-10(x2-30x-8x+240)
=-10(x2-38x+240)
=-10[(x2-19*2x+19*19)-19*19+240]
=-10[(x-19)2-361+240]
=-10(x-19)2-1210