Question 1088542

slope = m = (y2-y1)/(x2-x1) = (z-9)/(0-2) = (z-9)/(-2) = 8

z-9 = -16
Ans:   {{{ highlight(z = -7) }}}

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Check:   (-7-9)/(0-2) = -16/(-2) = 8 (ok)
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On a side note: you are free to choose which point is (x1,y1) and (x2,y2).  I chose (x1,y1)=(2,9) and (x2,y2)=(0,z) but you can prove it to yourself by reversing them.