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Home Q & A Board Science-Related Homework Help Mathematics
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ilikebigbutts ilikebigbutts
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11 years ago
I have several of these equations to solve and I don't even know where to begin. Can someone break it down for me on how to work this equation? I'll be able to figure out the others once I see how it's done.

3x - y = -2
5x = y

Any help is greatly appreciated. Thank You.
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wrote...
#1
11 years ago
3x - y = -2
5x = y

in the first equation, replace y with 5x:
3x - (5x) = -2
-2x = -2
x = 1
y = 5x = 5
wrote...
#2
11 years ago
3x + -1y = -2
5x = 1y

Think algebraically so change all subtraction to addition and think of a lone variable with a 1 in front of it.
wrote...
#3
11 years ago
Do you mean system of equations?
Assuming that:
Since y=5x according to the second equation, you can substitute 5x for y in the first equation.
3x - 5x = -2
-2x = -2
x = 1
Plug in 1 for x in 5x=y to find y. The equation can be turned around to
y = 5x
y = 5(1) = 5

answer: (1, 5)
wrote...
#4
11 years ago
Step 1... split up x and y
3x = y - 2
5x = y

Step 2... depending on the equation, you either want to add or subtract the equations..

Subtract...

-2x = 0y - 2

Step 3... solve

x = 1

5x = y.... x=1
5(1) = y
y = 5
wrote...
#5
11 years ago
From the bottom equation we can see that y is 5x. This can be 'substituted' in to the top equation.

We take the 5x and place it in the top equation instead of y (as 5x = y)
This gives:
3x - 5x = -2

which can be written as:
-2x = -2

if we divide both sides of this equation by -2 we get:
x = 1

Then we can use this in the bottom equation to give:
5*(1) = y

so y = 5

hope this helps
wrote...
#6
11 years ago
Okay, for starters let the first equation as #1 and the second as #2.

Since #2 has y=5x, we can use that to substitute for #1. So #1 will be 3x-5x= -2.

Combine the like terms and it will be -2x= -2. Simplify and x=1.

For #2, substitute x=1 to #2 so it will be 5(1)=y. Simplify and y=5.

The answers are x=1 and y=5.

Hope this helps!! ~Jyna
wrote...
#7
11 years ago
3x-y=-2
5x=y

3x-y=-2
-3x    -3x
--------------
-y=-3x-2
y=3x+2(now plug this into the other equation)

5x=y
5x=3x+2
-3x -3x
---------------
2x=2
/2  /2
x=1(now plug this into the other equation)

y=3x+2
y=3(1)+2
y=3+2
y=5


So x=1, and y=5. The proper way to write this is- (1,5)
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