Question

write the slope intercept form of the line parallel to the graph of 9x + 3y = 6 that passes through ( 0, 18)

Answer 1

`y = - 3x + 18`

Explanation:

Let's rearrange to slope-intercept form

`9x + 3y = 6 \\ 3y = 6 - 9x \\ divide \: both \: sides \: by \: 3 \\ y = 2 - 3x \\ y = - 3x + 2`

For a line to be parallel to another line they have to have the same slope.

So the slope of the new line,

'y = mx + c' will be 'y = -3x + c'

We then plug in the coordinates for the new line to find our 'c' value

`y = - 3x + c \\ (18) = - 3(0) + c \\ 18 = c \\ c = 18`

You could have also easily gotten it if you remembered that 'c' is the y-intercept, and at y-intercepts the x value is '0'

So we substitute '18'for our 'c' value in the new equation

`y = - 3x + c \\ y = - 3x + 18`