find the intersection point of the graphs of x+y=-3 and 3x+y=7?

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find the intersection point of the graphs of x+y=-3 and 3x+y=7?

2007-10-11 02:53:35 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

2 answers

x + y + 3 = 0
3x + y - 7 = 0

x + y +3 = 3x + y -7
-2x +10 = 0
x = 5

plug 5 back into the equation

5 + y = -3
y = -8

so @ x=5 y = -8 the lines intersect.

2007-10-11 02:59:16 · answer #1 · answered by a_talis_man 5 · 0⤊ 0⤋

- 3x - 3y = 9
3x + y = 7----ADD
- 2y = 16
y = - 8

x - 8 = - 3
x = 5

x = 5, y = - 8

2007-10-11 10:56:57 · answer #2 · answered by Como 7 · 0⤊ 0⤋