My question is :
Solve simultaneously
{|x−1|−|y−2|=1y=3−|x−1|
What I did :
y=3−|x−1| is given.
Thus y=3−(x−1) or y=3−(−(x−1)), and so y=4−x or y=2+x.
If y=2+x, then x−1=4−y(1) or y−2=x(2).
Substituting 1), we get |4−y|−|y−2|=1 or |y−2−1|−|y−2|=1.
I got here but I am not getting how to get the final solution. Any help would be greatly appreciated.
Answer
You have that |x−1|−|y−2|=1. This gives us that |x−1|=1+|y−2|.
Plugging this into the second equation gives us y=3−(1+|y−2|)=2−|y−2|
This gives us that y+|y−2|=2.
If y≥2, then we get that y+y−2=2⟹y=2
If y<2, then we get that y+2−y=2
which is true for all y<2. Hence we get that y≤2
From the second equation, we get that |x−1|=3−y
Note that since y≤2, 3−y>0 always.
If x>1, then x−1=3−y⟹x=4−y
Note that 4−y>1, since y≤2.
If x≤1, then x−1=y−3⟹x=y−2
Note that y−2≤1, since y≤2.
Hence, the solution set is given as follows. y≤2 and x=4−y or y−2
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