matlab求解方程错误

matlab求解方程错误为什么我这段程序没法求解：clearclcDel=251;Det=0.002332;Eya=201000;Kcss=695;ncss=0.11;[x,y]=solve('x*y=Del*Det','x=y/Eya+2*(y/(2*Kcss))^(1/ncss)')x =[ empty sym ]y =[]而直接把数值代入就能求解呢?>> [x,y]=solve('x*y=251*0.002332','x=y/201000+2*(y/(2*695))^(1/0.11)')x =0.0017094310965750456304996030283991y =342.41333340241092045873244743749