三道数学题,急
问题描述:
三道数学题,急
1.当x为何值时,代数式(2x+9/x+3)-(1/x-3)与2+(2/x)的值相等?
2.当a为何值时,关于x的方程2ax+3/a-x=5/4的根是1?
3.当m为何值时,关于x的方程2x-3/x-2=m+4/x-2会产生增根?
答
(1)(2x+9)/(x+3)-1/(x-3)-2/x=2 (2x+6+3)/(x+3)-1/(x-3)-2/x=2 2+3/(x+3)-1/(x-3)-2/x=2 3/(x+3)-1/(x-3)-2/x=0 3/(x+3)=1/(x-3)+2/x 3/(x+3)=[x+2(x-3)]/[x(x-3)] 3/(x+3)=(3x-6)/[x(x-3)] 1/(x+3)=(x-2)/[x(x-3)] ...