Additonal Maths line equations

I've noticed in mark schemes, the equation of graphs is in the format ax+by=0. If I give the correct answer in the form y=mx+c, does it make a difference?

I've noticed in mark schemes, the equation of graphs is in the format ax+by=0. If I give the correct answer in the form y=mx+c, does it make a difference?

As long as the question doesn't specify it, you won't lose marks. However, whilst y=mx+c is the way you're taught to do it at GCSE, there are a number of advantages with ax+by=0. Especially if you find yourself getting fractional coefficients with mx+c, it's not a bad idea to get into the habit of ax+by when it's appropriate.

How exactly do you do it? For example: y= -0.75x+1.75

That function is equal to $y=-\frac{3}{4}x+\frac{7}{4}$. So we just multiple both sides by 4 to get $4y=-3x+7$ and then move everything to one side to get $4y+3x-7=0$. You'll find that it's a lot better to keep things in fraction form than decimal form.