1个图形用6根火柴,2个图形用11根火柴,3个图形用16根火柴,问N个图形用多少根火柴?

问题描述:

1个图形用6根火柴,2个图形用11根火柴,3个图形用16根火柴,问N个图形用多少根火柴?