Let \( t \) be the number of weeks.
The height of the first plant (on the windowsill) can be expressed as: \[ h_1 = 14 + 10t \]
The height of the second plant (on the coffee table) can be expressed as: \[ h_2 = 49 + 3t \]
We want to find when the heights of both plants are equal: \[ 14 + 10t = 49 + 3t \]
Now, we will solve this equation.
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Subtract \( 3t \) from both sides: \[ 14 + 10t - 3t = 49 \] \[ 14 + 7t = 49 \]
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Subtract 14 from both sides: \[ 7t = 49 - 14 \] \[ 7t = 35 \]
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Divide by 7: \[ t = 5 \]
Now we substitute \( t = 5 \) back into the equations for the heights of the plants.
For the first plant: \[ h_1 = 14 + 10(5) = 14 + 50 = 64 \text{ centimeters} \]
For the second plant: \[ h_2 = 49 + 3(5) = 49 + 15 = 64 \text{ centimeters} \]
Thus, in \( \boxed{5} \) weeks, each plant will be \( \boxed{64} \) centimeters tall.