A class collects $50 to buy flowers for a classmate who is in the hospital. Roses cost $3 each, and carnations cost $2 each. No other flowers are to be used. How many different bouquets could be purchased for exactly $50?_______
函数y=当时,函数的值域为___________________
已知幂函数y=f(x)的图像过点(3,),则函数f(x)=__________;
已知函数,则其必过定点________;
圆心为C(3,-5),且与直线x-7y + 2 = 0相切的圆的方程为 。
、圆x2+y2-4x+6y+9=0的点,其中到直线x-y+2=0的最远距离是