The slope is 1, so m = 1.
The given point is (x,y) = (1,5) which means x = 1 and y = 5 pair up together.
Plug the three pieces of info (m = 1, x = 1, y = 5) into the y = mx+b equation. Then solve for b
y = mx+b
y = 1*x + b ... replaced m with 1
5 = 1*1 + b .... replaced x with 1, replaced y with 5
5 = 1+b
1+b = 5
b+1 = 5
b+1-1 = 5-1
b = 4
Since m = 1 and b = 4, we know that y = mx+b turns into y = 1x+4 which simplifies to y = x+4
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Answer: y = x+4
