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Andrea’s work to find the equation of a trend line through the points (48, 61) and (72, 195) is shown below. Andrea’s Work Step 1 m = StartFraction 72 minus 48 Over 195 minus 61 EndFraction = StartFraction 24 Over 134 EndFraction = StartFraction 12 Over 67 EndFraction Step 2 61 = (StartFraction 12 Over 67 EndFraction) (48) + b Step 3 b = StartFraction 3,511 Over 67 EndFraction Step 4 y = StartFraction 12 Over 67 EndFraction x + StartFraction 3,511 Over 67 EndFraction What was the first error that Andrea made?

A- Andrea used the reciprocal of the slope.

B- Andrea made a computational error when she simplified m.

C- Andrea substituted incorrectly when she solved for b.

D- Andrea made a sign error when she solved for b.