Answer:

Step-by-step explanation:
Given


Required
Find a and b
Substitute
for x and y in 



Rewrite as:

The above implies that (a) is correct;
Hence:

So, the equation is:

Answer:
Second one
Step-by-step explanation:
if 2x - y = 4
then 2x + 4 would have to = y
The equation where 2x + 4 = y is the second
y = 2x + 4
Answer:
Monday
Step-by-step explanation:
Day 1 (Monday):
10 minutes to seconds: 10 x 60 = 600 seconds
= 0.67 m/s
Therefore day 1 she ran at 0.67 m/s
Day 2 (Tuesday):
25 minutes to seconds: 25 x 60 = 1500 seconds
= 0.55 m/s
Therefore day 2 she ran at 0.55 m/s
She was faster day 1 (Monday)!