Question 30889
y =x +9
x +9y =21
x +9(x+9) =21
x + 9x + 81 = 21
10x=-60
x=-6
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y =x +9
y=(-6)+9
y=3
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these systems have different slopes, so they are perpendicular (independent;consistent)
the point they intersect is: (-6,3)