> multiply the second equation by 2 and add it to the first equation.
2(-6x - 7y = -10)
-12x -14y = -20
8x + 14y = 4
-12x - 14y = -20
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- 4x + 0 = - 16
x = -16/-4
x = 4
> use x = 4 in either equation to find y
8(4) + 14y = 4
32 + 14y = 4
14y = 4 - 32
14y = -28
y = -28/14
y = -2
Lets say you have 5 apples, but the you give away 3 of them.
To work how many you have left you take away.
5-3 = 2
Lets apply this with fractions now.
You have 9/7 yard, but then you give away 7/20 yard.
Now you take them away:
9/7 minus 7/20 = 131/140
Hope this helps :)
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