5x²-mx+n 因式分解 ﹙5x-60﹚﹙x+20﹚ 求m,n
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5x²-mx+n 因式分解 ﹙5x-60﹚﹙x+20﹚ 求m,n
﹙5x-60﹚﹙x+20﹚
=5x²+100x-60x-1200
=5x²+40x-1200
=5x²-mx+n
-m=40, m=-40
n=-1200
5x²-mx+n =﹙5x-60﹚﹙x+20﹚=5x²+40x-1200
m=-40
n=-1200
﹙5x-60﹚﹙x+20﹚
=5x²+100x-60x-1200
=5x²+40x-1200
由原式5x²-mx+n 可知
m=-40 n=-1200
答案:m=-40,n=-1200
﹙5x-60﹚﹙x+20﹚去括号:
=5x^2+100x-60x-1200
=5x^2+40x-1200
对应5x²-mx+n 项相等
得:m=-40,n=-1200