Line AB passes through points A (6,6) and B(12, 3). If the equation of the line is written in slope-intercept form, y=mx+b, what is m and b?

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Answer 1 · 2016-12-01T15:59:15

$m=-2," "b=18$

eqn. of a straight line with known co-ordinates

$(x_1,y_1)," "(x_2,y_2)$

is given by the formula

$(y-y_1)/(x-x_1)=(y_2-y_1)/(x_2-x_1)$

for $A(6,6)," "B(12,3)$

$(y-6)/(x-6)=(12-6)/(3-6)$

$(y-6)/(x-6)=6/-3=-2$

$y-6=-2(x-6)$

$y=6+(-2x)+12$

$y=-2x+18$

$m=-2," "b=18$