geometry
posted by gg .
Martha works as a salesperson for momentum sales. she earns $1,000 per month plus 15% commission on her sales.
a. write an equation that expresses t, her income for one month as a function of x, her total sales for the month.
b. River City Sales, another company in the same town, has offered Martha a job that will pay her $500 per month plus 20% commission on her sales. Explain why Martha should or should not accpet the job at River CIty Sales. Support your answer by finding x, the average total sales for the month she would need to at least equal her present income at Momentum Sales.

Why are you calling this a geometry question? It looks like business math, or algebra.

Momentum Sales: t = .15x + 1000
River City Sales : t = .20x + 500
Set the two right sides of the above equations equal to each other and solve for x, you should get x = 10,000
That will give you the sales she needs to make the same money.
Draw your conclusion by substituting a value of x less than that, and a value of x greater than that in those two equations.
I guess you called your question "Geometry" because they want you to graph your two equations.