Acell phone store sells the basic model of a phone for $30 and the upgraded model for $100 when a customer signs a two-year agreement. on tuesday, the store has $900 in sales. the store pays $5 for each basic model and $25 for each upgraded model. if the cost of the cell phones sold on tuesday is $200, how many upgraded models were sold?

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)