HELP ASAP Find an expression which represents the sum of (6x - y) and (7x - 7y) in simplest terms.​

Solve the inequality. write the inequality in interval notation. 9(t-2)> 3(t-7)

Solve the system of equations. y= 2x y= x^2 - 15

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