Answer:
629.92 
Step-by-step explanation:
The minimum volume of the can that can hold 4 tennis balls must have at least the same volume as 4 tennis balls.
The volume of one tennis ball, V = 
where r = radius of the tennis ball
The diameter of a ball = 6.7 cm
Its radius will be = 6.7 / 2 = 3.35 cm
Volume, V, will be:

V = 157.48
Hence, the volume of 4 balls will be:
4 * V = 4 * 157.48 = 629.92 
The minimum volume that the cylindrical can has to have is 629.92
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1/5 out of 50 I think is 8
I'm not 100% sure though
X= -2
Y= -1
Z= 1
You may use solve this problem by substituting the values as well. If everything goes wrong , go for Cramer’s rule
Im not exactly sure but i think:
r^2+6r+2
________
5r^2-5r-25
remember IM NOT SO SURE