SOLUTION: I really don't understand the process for solving this type of problem. I've got all kinds of formulas and whatnot but I do not know which to use or when or if I even have the righ

Algebra ->  Graphs -> SOLUTION: I really don't understand the process for solving this type of problem. I've got all kinds of formulas and whatnot but I do not know which to use or when or if I even have the righ      Log On


   



Question 289404: I really don't understand the process for solving this type of problem. I've got all kinds of formulas and whatnot but I do not know which to use or when or if I even have the right ones...
Find the equation for the line parallel to the line 3x+6y=-8 having the same y-intercept as -5x-5y=6.

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


In order to create an equation of a line, you need two pieces of information. You either need the ordered pairs representing two points, or you need a point and the slope (from which you can calculate the coordinates of any other point).

You are given the equation of a line and you want a line parallel to that line. The first thing to realize is that parallel lines have identical slopes. That is:



Two ways to find the slope given an equation. You can either put the equation into slope-intercept form, which is to say solve it for in terms of everything else. Then the slope is the coefficient on . Or, if the equation is in Standard form like the one in your problem, divide the negative of the coefficient on by the coefficient on .

The point you need is the point where the other given equation intersects the vertical axis. This is the point where is zero. So, substitute zero for in and do the arithmetic to find the value of . That will give you a point where is the value you just calculated for .

Now that you have the slope of the desired line and one point on the desired line, you can use the Point-Slope Form to create the desired equation.



Where is the slope you calculated and are the coordinates of the intercept point that you calculated. In this case the coordinates will be because it is the intercept.

You should be able to get to the end from here.


John