What is 13/50 simplified

Can (3,5 and square root 34) be sides on a right triangle?

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

What is the value of x in the following equation? -3x-2=2x+8