X²-17.5x+75=0怎么解

问题描述:

X²-17.5x+75=0怎么解

x²-17.5x+75 = 0 ,
(x-10)(x-7.5) = 0 ,【十字相乘法:10+7.5 = 17.5 ,10*7.5 = 75 】
x = 10 或 x = 7.5 .