Solve the system of equations.
y= 2x + 3
y=x+3x+3

What fraction of one year is 8 months

Three coins are flipped. what is the probability that there will be at least two tails?

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