Please help me find how to write an equation in slope-intercept form.

Question

Ricardo wants to by a phone that costs $1,150. He will make a down payment of $250 and will make monthly payments of $50. Write an equation in slope-intercept form that Ricardo can use to determine how much he will owe after n months.

Answer 1

1150 - 250 = 900

-50*n + 900

incidentally

0 = -50*n + 900

-900 = -50*n

90 = 5n

n = 18

will be paid off in 18 month , unless there is interest