Explanation:

You know 2 points which are [as you are told it passes x-axis through which occurs when ] and .

An equation of a straight line is in the form: where and are your variables, is your gradient and is your y-intercept.

Gradient is calculated by where and are two co-ordinates.

Use this gradient value and any co-ordinates to find the general form of the equation using where are any co-ordinates of the line.

The method and working out:

The two co-ordinates are and .

Check this with the other co-ordinates, .

Therefore the equation of the line is .