Answer: y = x+15
This is the same as y = 1x+15
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Work Shown:
The two given points are
(x1,y1) = (4,19)
(x2,y2) = (9,24)
Use the slope formula
m = (y2-y1)/(x2-x1)
m = (24 - 19)/(9-4)
m = 5/5
m = 1
The slope is 1.
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Pick one of the points and plug those coordinates into y = mx+b along with m = 1. I'll plug (x,y) = (4,19) into the equation
y = mx+b
19 = 1*4+b
19 = 4+b
4+b = 19
b+4 = 19
b+4-4 = 19-4 ... subtract 4 from both sides
b = 15
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m = 1 and b = 15 makes y = mx+b turn into y = 1x+15 or simply y = x+15
