For 1 hour:
- Jennifer can clean 1/2 of her room;
- John cal clean 1/5 of her room.
Both can clean: 1/2 + 1/5 = 5/10 + 2/10 = 7/10
1 hour -------- 7/10
x hours---------- 1
x = 1 : 7/10 = 10/7 h = 1.42857 h ( or 1 h 25 min 43 s )
They are:
0.27
1.60
6.47
2.57
9.00
44.56
49.29
325.17
Do you mean an extraneous solution? I will tell you what I think. To tell if a solution is extraneous you need to go back to the original problem and check if there actually is a solution or if the solution is actually right. If not then it is extraneous.
Answer:

Step-by-step explanation:

Answer:
5,-1
Step-by-step explanation:
2,3
+<u> 3,-4</u>
5, -1