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Coordinate Geometry
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heshamelaziry
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any two lines that are not parallel intersect at one place.
There are 2 strategies to go from 2 variables (x and y) to 1 variable. Once you solve for one of the variables, you can then plug into either equation and solve for the other.
y = 5x - 3
y = -4x + 6
1) Subtract equations:
y - y = (5x - 3) - (-4x + 6)
0 = 9x - 9
9 = 9x
x = 1
2) Set y's equal:
5x - 3 = -4x + 6
9x = 9
x = 1
Plug x=1 into either equation and you get y = 2.
Point (1,2) is your solution.
There are 2 strategies to go from 2 variables (x and y) to 1 variable. Once you solve for one of the variables, you can then plug into either equation and solve for the other.
y = 5x - 3
y = -4x + 6
1) Subtract equations:
y - y = (5x - 3) - (-4x + 6)
0 = 9x - 9
9 = 9x
x = 1
2) Set y's equal:
5x - 3 = -4x + 6
9x = 9
x = 1
Plug x=1 into either equation and you get y = 2.
Point (1,2) is your solution.
