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Week 4 Presentation: Graphic Equations Math 114N
The Problem:You are moving and need a rental truck. The rental company you have chosen charges a $70/day fee plus $0.20 for every mile you travel. Write a linear equation that expresses the total cost y, where x represents the number of miles you travel. Graph this equation. Then choose a number of miles, x, you travel that day and find the total cost of renting the truck.
The Linear Equation for problemWe have two numbers important to the problem:$.20 per mile and $70 per daySo we have Y representing the total it’ll cost us. Thus making the equationY= .20x + 70
Finding the points So we already know that the linear equation will be a straight line. The reason for this is because nothing in the equation is cubed or squared which will typically cause a line to be curved. For the first I will use: x=0So 0 or the x place will represent (the miles drove)So when I plug 0 into the equation:Y= .20x + 70Y=.20(0)+70Y=0+70Y=70Now the second: when x=1So now I plug 1 for the miles drove into the equation:Y= .20x + 70Y=.20(1)+70Y=.20+70Y=70.20
Now Lets Graph! So previously we found our points which are:70 and 70.20But we can’t plot points like this..(0, 70 ) and (1, 70.20)(0,70)(1,70.20)
How much the truck will cost me...So now we are to decide how far I am to travel and find the cost. I’m planning on driving 2000 miles in the rental truck.All we have to do is plug in for x. Because if we remember the x variable represents the number of miles I am traveling. Thus:Y=.20x+70Y=.20(2000)+70Y=400+70Y=$470So if I needed to drive the truck 2000 miles to my destination the rental truck will cost me $470.