Question 626745
Find c so that x-3y=c is not parallel to 2x-6y=10.
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c does not affect the slope. They are parallel.
There is no c which will make the not parallel.
If c = 5, the are coincident, the same line, but that is still the same slope = parallel.
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Show that ax+by=c and bx-ay=kare perpendicular.
ax+by=c
m=-a/b
bx-ay=k
m=b/a
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The 2 slopes are negative inverses --> perpendicular.