What value of n in the equation nx 2=6y would give a line with slope 4?

The slope is defined as y/x. That means that we'll need to have y/x = 4.

So, first we transform the equation to form n = 6y / 2x => n = 3y/x.

Second, we substitute y/x with 4 and get n = 3 * 4.

Obviously the result is n = 12.

I hope this helps.