If the roots of the equation x2−2ax+a2+a−3=0 are real and less than 3, then
Solution : x2−2ax+a2+a−3=0 D=4a2−4(a2+a−3)≥0 a−3≤0 a≤3 f(3)=9−6a+a2+a−3>0 a2−5a+6>0 (a−2)(a−3)>0 a<2 or a>3 2aa<3 a<3 (a<2)