Equation of the straight line can be given in more form. The most common forms are implicit (general or standard) form ax+by+c=0 and explicit form y=kx+i, where k is line coefficient and l is cut which line made on the y axis. If k>0 then the angle that takes straight line with the positive direction to the x axis is sharp and if k<0 then the angle that takes straight line with positive direction to the x axis is obtuse. In you case you only need to form one monomial with variable y in the given equation in the following way: 3x-4y+7=3y => add to both side (-3y) and you get 3x-4y-3y+7=3y-3y finally we get implicit or general 3x-7y+7=0. If is it necessary to transform from the implicit into the explicit form we will do this in the following way: 3x-7y+7=0 add to both side expression (-3x-7) => 3x-3x-7y+7-7=-3x-7 => divide both side with (-7) => y= (-3x-7)/ (-7) => finally we get y=3/7 x + 1 ( in our case coefficient of direction k=3/7 and the cut which line is made3 on the y axis l=1). Its display in the decartes coordinate system is given in one of the already given answers.
This is simple :) If 9 chairs can fit in one box, and you have 3,456 chairs, just divide how many chairs you have by how many can fit in the box in order to find how many boxes you will need.
