已知等比数列{an}的前n项和为Sn,若S4、S2、S3成等差数列,且a2+a3+a4=﹣18,若Sn≥2016,则n的取值范围为____
下列方程组中,是二元一次方程组的是( )
He puts five ____ (pound) into the bottle every day.