It cannot be -1 because that would make the slope positive, but the slope is negative. If the slope is negative, then you go down y and over to the right x. It cannot be 0, because the line would then be undefined. Therefore, 6 is the only possible answer.

AleksandrM wrote:It cannot be -1 because that would make the slope positive, but the slope is negative. If the slope is negative, then you go down y and over to the right x. It cannot be 0, because the line would then be undefined. Therefore, 6 is the only possible answer.

Good explanation Aleksander.
With these types of questions ... I always find it useful to draw out a picture on my scrap paper ... so with this question you can see that the value of x will be positive. It cannot be 0 ... and it cannot be negative. So this leave 6 as the only possible answer.

However, I would be keen to see if anyone has an alternative approach to solving this.
I couldnt really use or do much with the "y = mx + c" equation of line here.
We have the following values: y=4, c=4 (the y-intercept), and x=0 here. So we have one coordinate (0,4) ... but we need another coordinate to get m ... so not really much use.

Any comments/other approaches ?

Thanks.
II