Michael J. answered 07/11/15
Tutor
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Effective High School STEM Tutor & CUNY Math Peer Leader
Use the distance formula:
d = √[(x1 - x2)2 + (y1 - y2)2]
d = 11 - 9t
Point 1 = (1 , 2t)
Point 2 = (1 - t , 1)
Plug in these values into the formula.
11 - 9t = √[(1 - (1 - t))2 + (2t - 1)2]
11 - 9t = √[(t2 + (4t2 - 4t + 1)]
Square both sides of the equation and expand.
121 - 198t + 81t2 = 5t2- 4t + 1
Move all the terms to the right side.
0 = -76t2 + 194t - 120
Use the quadratic formula to solve for t.
t = (-b ± √(b2 - 4ac)) / 2a
where:
a = -76
b = 194
c = -120
Plug in these values, and you are all set.