求圆心在 $\left({\rho }_{\circ },{\theta }_{\circ }\right)$ ，半径为r的圆的方程

化简：（3x+2y+1）²﹣（3x+2y﹣1）（3x+2y+1）

    My teacher Mr. Li is a y____ man, about 25 years old. He is a h____ teacher, working(工作) at school from 7:30 in the morning to 18:30 in the e____. It seems(仿佛) that he has many things to do every day. Although he's b____ with his work and has no time to play, after class he likes playing f____ with boys in the playground. Look! He's kicking the ball! We all like him very much.