t(3-t)=30 = 3 + t^2 - 3t(t-3/2)^2 - 9/4 + 3 =0(t-3/2)^2 + 3/4 = 0(t-3/2)^2 = - 3/4 = (-1) * 3/4 = i^2 * (根号3 /2)^2t-3/2 = ±根号3 i /2t= 3/2 ± i(根号3)/2i是虚数单位。这不是实数解,这方程没有实数解。
约分先,t2-3t+3=0 T2-3t+9/4=-3+9/4 就可以算出来了