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3x + 2y = 8 y = 4x – 7

 

i need to solve for x and y

 Apr 23, 2019
edited by Guest  Apr 23, 2019
edited by Guest  Apr 23, 2019
 #1
avatar+34 
0

This is a simple algebra problem. You set X to set and get the value for X. You do the same thing for Y. 

 

Once you get these vales, just plug them into your problem. 

 Apr 23, 2019
 #2
avatar+18293 
+1

3x + 2y =8        y = 4x-7    SUb second equation in to the first...then solve for x

3x + 2 (4x-7) = 8

3x +8x -14 = 8

11x = 22

x = 2                        Use this value of x to sub back in to one of the original equations to find y

 

y = 4x-7

y = 4(2) - 7

y = 1                         so the solution point is  (2,1)

 Apr 23, 2019
 #3
avatar+44 
-5

As listed above, others used substitution, but you can use elimination as another way to solve it

 

 

Using substitution is easiest because it already tells you what y is in terms of x

 

Elimination:

We try to subtract/add the two sentences to remove the extra variable

I can multiply 3x+2y=8 by 4 to get 12x+8y=32

I can them multiply y=4x-7 by 3 to get 3y=12x-21

Now by subtracting these two sentences I can remove the x value

 

After I get rid of my x value, the y variable will be the only variable left, where we can now solve the Algebra equation.

 Apr 23, 2019

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