66. 10a-4
67. 7x+y
68. -4k-9
69. -21x-15
70. 100y+6
71. -88r-9s
72. 24x-25t
73. 20a-10b-6c
Chris is going 10 mph. After 9 hours, Chris has gone 90 miles. Elena is going 14 mph. After 9 hours, she has gone 126 miles. 126 miles is 36 miles more then 90 miles.
.75 miles a day.
30/.75=40
It will take Tanya 40 days to reach her goal.
2.64575131106.. or you can round it but it is irrational because rational numbers either stop or repeat irrational don't
Negative reciprocals of each other