z=(x-40)[20-(x-100)/10]怎么化成顶点式来……不好意思,忘了

问题描述:

z=(x-40)[20-(x-100)/10]
怎么化成顶点式来……不好意思,忘了

z=(x-40)(-x/10+30)
=-x²/10+34x-1200
=-1/10(x²-340x+28900-28900)-1200
=-1/10(x²-340x+28900)+2890-1200
=-1/10(x-170)²+1690