What’s the 4th term in the sequence?

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

Which is the graph of this function 3 square root of x plus one if

Find the maximum value of p= 4x + 5y subject to the following constraints :