Explain the Error: Alan says that two lines in the coordinate plane are perpendicular if and
1 answer:
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Um
first note that x=-7 is not allowed in the soltions set
multiply both sides by x+7
make a sign chart and input values and see what they are
ok so we know we have zeroes at x=-9 and x=11
and x=-7 is not allowed so
see attachment
at x=-10,, we get a negative sign so it is less than 0
at x=-8, we get a positive sing, so it is more than 0
at x=-3, we get a negative sign, so less than 0
at x=20, we get a positive sign,so greater
so then
we do from negative inity to -9
and not between -9 and -7
between -7 and 11
so then
(-infinity,-9)U(-7,11]
first note that x=-7 is not allowed in the soltions set
multiply both sides by x+7
make a sign chart and input values and see what they are
ok so we know we have zeroes at x=-9 and x=11
and x=-7 is not allowed so
see attachment
at x=-10,, we get a negative sign so it is less than 0
at x=-8, we get a positive sing, so it is more than 0
at x=-3, we get a negative sign, so less than 0
at x=20, we get a positive sign,so greater
so then
we do from negative inity to -9
and not between -9 and -7
between -7 and 11
so then
(-infinity,-9)U(-7,11]