Question 393643: find the intersection of x+3y-3=0 and 2x-7y+20=0 (Please show your solution. THanks!)
Answer by nerdybill(7384)   (Show Source):
You can put this solution on YOUR website! Solve both equations for y:
x+3y-3=0
x+3y = 3
3y = -x + 3
y = (-1/3)x + 1
.
and
2x-7y+20=0
2x-7y= -20
-7y= -2x - 20
y= (2/7)x + 20/7
.
set them equal to each other:
(-1/3)x + 1 = (2/7)x + 20/7
multiply both sides by 21:
-7x + 21 = 6x + 60
21 = 13x + 60
-39 = 13x
-3 = x
.
to find y plug into:
y = (-1/3)x + 1
y = (-1/3)(-3) + 1
y = (1) + 1
y = 2
.
intersection is at: (-3, 2)
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