Math CentralQuandaries & Queries


Question from Zachery, a student:

i have a slope that equals 1/1 and my coordinates are (-22;-1) and (-23;-2) and i am trying to change it into the equation y=mx+b and the farthest that i've gotten is y=1x_ (i can not find out how to find b.) So i was wondering if you could help me find out what b is because i have got no clue!!!!!


You are so close.

You found the slope to be 1 so m = 1 in the equation y = mx + b. Thus

y = 1x + b or
y = x + b.

But you know that (-22; -1) is on this line so substitute x = -22 and y = -1 into the equation above and solve for b.

After you find b you can check your answer. (-23; -2) is also on the line so substitute x = -23, y = -2 into the final equation and see if the equation is valid for these values of x and y.


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