Question:
I have a few math ?'s i really need help.?
Drew L
2009-05-20 07:16:30 UTC
1. Use a graph to solve problem 6x + 3y=6
2x + y = 2 do they cross?

6. Graph they equations
x - y= -2
2x + y = 5

14. The triangle with side lengths is 12,16,20 is a right triangle
True/sometimes/false

I really need help in these if any one can answer one of these or all it would be so great so thanks in advance.
Three answers:
Evan
2009-05-20 07:52:25 UTC
1)

First step is to get the x on the right side of the equal sign and the y on the left without any coefficients.



For the first equation: 6x + 3y = 6, we subtract 6x from both sides and get:

3y = - 6x + 6, then we divide all expressions by 3:

3y/3 = -6x/3 + 6/3, which gives us the first equation in general form: y = - 2x + 2.



We do the same for the next equation:

2x + y = 2, we subtract 2x from both sides of the equation:

y = - 2x + 2, which gives us the second equation in general form



We then have to graph the equations. I'd suggest making a table of values. Then draw up your axies plot the points, join the dots and continue the line to the end of your axies.



y = - 2x + 2:



x -3 -2 -1 0 1 2 3

y 8 6 4 2 0 -2 -4



Because both equations are exactly the same, they do not cross at one point.



6)

We do the same as we did above, we move the x on the right side of the =, the y on the left and without any coefficients.

x - y = -2, the first thing we do is subtract x from both sides of the equation:

-y = -x - 2, the second thing we do is divide every expression by -1 to remove the - sign from the y;

-y/-1 = -x/-1 -2/-1, this gives us the general form of the equation:

y = x + 2,



We do the same with the second equation by following the steps above:



2x + y = 5, we subtract 2x from both sides of the equation:

y = -2x + 5.



We then graph the equations. We draw up our table of values, plot the points, join the dots and continue the line to the end of your axies:



y = x + 2:



x -3 -2 -1 0 1 2 3

y -1 0 1 2 3 4 5



y = - 2x + 5:



x -3 -2 -1 0 1 2 3

y 8 6 4 2 0 -2 -4



All you have to do is use the tables above to plot the points on your graph and then draw your line, making sure it intersects all the points
Jenn
2009-05-20 07:37:54 UTC
The first two are graphing so I can really show it here unfortunately. How ever I can help ya graph a little bit.



1.The first thing that you need to do is rewrite the equations into the form of y=mx+b which is astandard point slope formula of a line.



6x+3y=6

(6x+3y) - 6x = (6)-6x

3y = -6x + 6

(3y)/3 = (-6x + 6)/3



y = -2x + 2





The second one would be:



2x + y = 2

(2x + y) - 2x = (2) - 2x



y = -2x + 2



Now you would graph both of lines, and as you'll see, they're the same line, so no they would cross because they're the same!



6. Do the same thing with putting them into y=mx+b



x-y = -2

(x-y) - x= (-2 ) - x

-y = -x - 2

-1 * (-y) = -1*(-x - 2)



y = x+2



2x + y = 5

(2x + y)-2x = (5) - 2x



y = -2x + 5



Now just graph those two equations



14. True
Harley Odeen
2009-05-20 07:21:57 UTC
14. is true


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