Answer: 54 mph
Step-by-step explanation:
d-the distance
s+9 - the speed to the conference
d=6*(s+9)
s- is the speed on the way back home
d=7*s
so 6*(s+9)=7*s
6s+54=7s
-6s -6s
54= 7s-6s
s=54 mph
The answer is the third choic, or the line with the same slope.
Do you mean 90(3n-6) if so the answer is -270 but if you mean 3n-6 the answer is -3