若方程3x-2y=IaI的解x,y的值也满足Ix+2y-1I+(x-3y)的平方=0,求a的值
问题描述:
若方程3x-2y=IaI的解x,y的值也满足Ix+2y-1I+(x-3y)的平方=0,求a的值
答
Ix+2y-1I+(x-3y)的平方=0因为Ix+2y-1I>=0 (x-3y)的平方>=0则 x+2y-1=0 x-3y=0 --> x=3y3y+2y-1=05y=1y=1/5 x=3*1/5=3/53x-2y=3*3/5-2*1/5 = 9/5-2/5=7/5=|a|a=7/5 或 a=-7/5