Question

How do you write the equation of the line with slope m = 3 and including point (3, 5)?

Answer 1

The equation of a line is

`y = mx + c`

and `m` is already given as `3`.

Therefore,

`y = 3x + c`

where `c` is found by substituting a point, which is given as `(3,5)`.

If `x = 3` and `y = 5` (as it says in the point given), then

`5 = 3*3 + c`
`5 = 9 + c`
`c = -4`

which we can substitute back in to give

`y = 3x - 4`

Answer 2

y = 3x - 4

Explanation:

One form of the equation of a line is : y - b = m(x - a )

where m represents the gradient (slope ) and (a,b) a point on the line.

here m = 3 and (a,b) = (3,5)

substituting these values into the equation.

y - 5 = 3(x - 3) → y - 5 = 3x - 9 → y = 3x - 4