To find out how long it would take the chef to prepare a dish containing 8 ingredients, we can substitute \( x = 8 \) into the equation of the line of best fit:
\[ y = 1.8x + 12 \]
Substituting \( x = 8 \):
\[ y = 1.8(8) + 12 \]
Calculating \( 1.8 \times 8 \):
\[ 1.8 \times 8 = 14.4 \]
Now, add 12 to this result:
\[ y = 14.4 + 12 = 26.4 \]
Therefore, it would take approximately 26.4 minutes for the chef to prepare a dish containing 8 ingredients.