Question

19) Geoff owns a computer store in 1990 he sold 2400 monitors and in 2000 he sold 4000. Let x represent the number of years since 1990. Write a linear equation in slope intercept form that represents this data. A) y = 160x + 4000 B) y=160x + 2400 C) y = 320x + 2400 D) y = 320x + 4000

Answer 1

We have the next informations

1990 ------ 2400

2000-------- 4000

the year 1990 represents x=0

for 2000 passed 10 years son x=10

we have then the next points

(0,2400) =(x1,y1)

(10,4000) =(x2,y2)

First we need to calculate the slope

`m=(y2-y1)/(x2-x1)`
`m=(4000-2400)/(10-0)=(1600)/(10)=160`

then we can calculate the linear equation

`y-y1=m(x-x1)`
`y-2400=160(x-0)`

the linear equation is

`y=160x+2400`

the correct answer is B