I am using the laws:
1)
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2)

3)

an x is a base - the law is valid if the bases are the same number!
The solution in attachment :)
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Solve the above equations,

First term is -13.
1) y=-x+4, the slope is -1
2)y=-x+4, slope is -1
3) yes
4)It's the same line if the slopes and y-intercepts are the same, so the number of corresponding points are infinite.
There are 14 groups of days are in 1 week.
45 degrees is the answer to your problem