题型:问答题 — How is that, Mary?— I wonder ________ it takes to be a good teacher beyond patience and a great knowledge of kids. [ ]A. how is it that B. what it is thatC. how it is that D. what is it that 查看答案
题型:问答题 已知关于x的方程(2k+1)x2-4kx+k-1=0,问: (1)k为何值时,此方程是一元一次方程?求出这个一元一次方程的根; (2)k为何值时,此方程是一元二次方程?并写出这个一元二次方程的二次项系数、一次项系数、常数项。 查看答案