Question

Mrs. Ferber graphed a line in class for her very bright students. The line passed through the points (6,-1) and (-2,3). She asked them to find the equation for the line and write it in standard form, Ax+By=C, with A≥0. Her brilliant students all correctly wrote the equation. What was the value of B?

Answer 1

first we find the slope
slope(m) = (y2 - y1) / (x2 - x1)
(6,-1) x1 = 6 and y1 = -1
(-2,3) x2 = -2 and y2 = 3
now sub
slope(m) = (3 - (-1) / (-2 - 6)
slope(m) = (3 + 1) / -8
slope(m) = 4/-8 or -4/8 which reduces to -1/2
so our slope is -1/2

now we will use y = mx + b
slope(m) = -1/2
you can use either of your sets of points...I will use (6,-1) x = 6 and y = -1
now sub and solve for b
-1 = -1/2(6) + b
-1 = -3 + b
-1 + 3 = b
2 = b

so our equation is : y = -1/2x + 2, but we want it in standard form
Ax + By = C

y = -1/2x + 2 --- multiply the entire equation by 2
2y = -x + 4 -- add x to both sides
x + 2y = 4 <=== standard form

So the value of B is 2

Answer 2

wow thanks you!!!!

Answer 3

sure thing :)

Answer 4

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