To predict your wages using the equation \( y = 0.75x + 30 \), where \( x \) is the number of phones assembled, you can substitute \( x = 100 \):
\[ y = 0.75(100) + 30 \]
Calculating this gives:
\[ y = 75 + 30 = 105 \]
Therefore, your wages if you assemble 100 phones in one day would be $105.00.