# Thread: 4 questions i can not figure out **HELP PLEASE**

1. ## 4 questions i can not figure out **HELP PLEASE**

I had 4 questions, i wrote em up in photoshop i thought it would be easier.

1.

2.

3.

4.

2. 1) using the line euqation
y = mx +c

where y = price
x = number of cds

substituting y = 490 and x = 80

490 = 80m + c -------(1)

similarly

640 = 200m + c -------(2)

solving the simultaneous equation:

m = 1.25
c = 390

final equation:

y = 1.25x + 390

3) the closest point on the line to the origin creates a line perpendicular which joins the origin and the point on the line closest to the origin to that particular line concerned.

given the equation of the line is 2x + y -2 = 0 → y = -2x + 2---------(1)
using
m1(m2) = -1
the gradient of the other line is 1/2

from y = mx +c
substituting the gradient of the new line
y = 1/2x +c

also since it passes through the origin (0,0)

0 = (1/2)(0) + c
c = 0

equation of new line:

y = x/2 ---------(2)

solving the simultaneous equation (1) and (2)

y = 2/5
x = 4/5