5x (10-x)X3=42怎么计算

问题描述:

5x (10-x)X3=42怎么计算

乘进去:3x(50x-5x2)=42
5x2-50x+14=0
⊿=50x50-4x5x14=2220
x=(50+-?(2220))/(2x5)=0.2883或9.7117

5x(10-x)3=42
5x(10-x)=14
50x-5x^2=14
-5x^2+50x-14=0
x=9.71169/0.2883