One of the two equations required in the system of equations needed to determine the dollar amount of phone and computer sales Houa made is y = x + 600.
Let x represents the dollar amount of phone sales Houa made, and y represents the dollar amount of computer sales she made.
Therefore, a system of equations that could be used to determine x and y can be written as follows:
y = x + 600 ........................................................... (1)
0.04x + 0.05y = 129 ......................................... (2)
Learn more about the system of equations here: https://brainly.com/question/21620502.
#SPJ1