You are gonna get rid of one of the variables. In this case x because it's the easiest.
4x + 8y =20
-4x + 2y =30
The x's cancel out leaving you:
8y=20
2y=30
Then you add:
10y=50
Then Divide:
y=5
Then to find x, you get rid of the y.
4x + 8y =20
-4x + 2y =30
I make the 8 negative so I have a positive x, and a negative 16 to cancel out the y.
2( 4x + 8y =20)
-8(-4x + 2y =30)
8x + 16y= 40
32x - 16y =-240
Then you add.
40x = -200
x=-5
Hope this makes sense! (:
You can put this solution on YOUR website! Right, so...
A.) 4x + 8y =20
4x5=20
So now 4x is cancelled out and 20 is subtracted from 20.
The result is 0.
8y=0
What can you substitute y with to get 0?
0?
8x0=0
In result:
x=5, y=0
That is just one of many answers.
B.) -4x + 2y =30
-4x-4=16
Now subtract that 16 from 30.
Surprise! You get 14 (mental math;)
2y=14?
Perhaps 7=y?
YES! 2 times 7 equals fourteen.
This gives us one of many possible results, (-4,7)
You're welcome.
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