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Question 903393: Solve each equation by graphing:
(x + y = 4
(x -y = - 2
Found 2 solutions by Fombitz, tutoringisfun:
Answer by Fombitz(32388)   (Show Source):
Answer by tutoringisfun(17)  (Show Source):
You can put this solution on YOUR website! first you have to solve for either x or y, since we want the form to be in y=mx+b,I will solve for y.
x+y=4 I subtract x from the from both sides: x+y-x=4-x, the x's on the left cancel each other out so I am left with the following:
y=4-x
which can be rewritten in slope intercept form as: y=-x+4 here the slope(m) =-1 and the y intercept(b) =4
I can now plot one point on my graph (0,4) to plot the line, I can either find the numerical value by substituting any integer for x or I can graph the line using the slope. Since the slope is 1 that means that from my point (0,4) I can go to the right one and up one or to the left one and down one:
for x-y=-2, we can follow the same steps as above. First you solve x-y=2 for y by subtracting x from each side as follows:
x-y-x=-2-x. the x's on the left cancel out leaving you with -y=-2-x. We can rewrite this as -y=-x-2. If you would prefer not to have a negative number as the slope, you can multiply the whole thing by a -1. -y(-1)=-x(-1)-2(-1)
this will eliminate the negative numbers leaving y=x+2.
There are 2 ways you can graph this equation. You can use the slope or plot points. I will use the slope. Since the slope is 1 that means that I start at my point (0,2) and go either to the right and up 1 integer or to the left and down 1 integer. Plot the point and connect the dots.
I hope this has been helpful to you. If you or your parents desire Algebra help for the school year or the duration of your course, check out my website as shown on my profile page or on twitter @mstngmom1 or http://www.liveperson.com/Experts/expertadvice.aspxat Thanks. You will find my rates there.
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