Respuesta :
Hello!
This is not an English question, but I'm glad to help.
If Lily bought four pairs of jeans at a cost of $39 per each pair, 4 x 39 = 149
The answer is 4 x 39 = 149 but to write a proper equation:
2 x 39 = 78
2 x 39 = 78
78 + 78 = 149
Toodles~