R+ 6r + 9 - 5r +6

a. 26r
b.1r + 15
c. 12r + 15
d. 2r + 15

Compare the subtraction problems 6/8 - 5/8 = 1/8 and 6/9 - 7/9 = 1/9 why is the answer to the first problem positive and the answer to the second problem negative

Aboard 60 in. long is cut two parts so that the longer piece is 5 times the shorter. what are the length of the two pieces?

Find the sum of the given arithmetic series. 24 + 17 + 10 + 3 + + (–39)