Question

A straight-line graph

• has gradient 4

• crosses the y axis at (0, −3).

Write down the equation of the graph.

Answer 1

Given:

A straight-line graph has gradient 4 and crosses the y axis at (0, −3).

To find:

The equation of the given graph.

Solution:

The slope intercept form of a line is:

`y=mx+b` ...(i)

Where, m is the slope of the line and b is the y-intercept.

A straight-line graph has gradient 4. It means the slope of the line is 4.

`m=4`

Line crosses the y axis at (0, −3). So, y-intercept is -3.

`b=-3`

Putting m=4 and b=-3 in (i), we get

`y=(4)x+(-3)`

`y=4x-3`

Therefore, the equation of the given line graph is
`y=4x-3`.