Answer:
There is no change.
Step-by-step explanation:
Notice that the denominators are 3 and 7, which are factors of 21.
So express all the fractions with denominator 21:
On Monday

are sold
On Tuesday

are sold
On Wednesday

are sold
by Thursday

of the tickets was sold.
Answer:
The temperature would be -10 degrees
Remember that moving on the x axis is 1 and on the y axis 2