1+4=5, 2+5=12, 3+6=21 , 8+11=? what the correct answer? /

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

Find the values of y: 3y^3(y^2+ 2/3y)=0

Which of the following represents the range of the graph of f(x) below