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Mathematics 20 Online
OpenStudy (anonymous):

simplify the expression.

OpenStudy (anonymous):

\[\sqrt{3}-4\sqrt{3}\]

OpenStudy (jdoe0001):

same as 1(a)-4(a), because the roots are the EXACTLY the same, they're treated as 1 literal per se

OpenStudy (anonymous):

\[-3\sqrt{3}\]

OpenStudy (jdoe0001):

yes

OpenStudy (anonymous):

\[4\sqrt{5}+5\sqrt{45} = 19\sqrt{5}\]

OpenStudy (jdoe0001):

yep

OpenStudy (anonymous):

\[5=\sqrt{k}+4=1\]

OpenStudy (jdoe0001):

yes, because \(1=\sqrt{k}\text{ and }1^2=(\sqrt{k})^2\)

OpenStudy (anonymous):

The formula \[v=\sqrt{64h}\] can be used to find the velocity v in feet per second of an object that has fallen h feet. Find how far the object has fallen if its velocity is 30 feet per second. Round your answer to the nearest hundredth.

OpenStudy (jdoe0001):

V=30feet and thus \( \implies 30 = \sqrt{64h}\)

OpenStudy (anonymous):

14.06

OpenStudy (anonymous):

feet

OpenStudy (jdoe0001):

yes

OpenStudy (anonymous):

solve the equation and identify any extraneous solutions. \[q=\sqrt{-7q}\]

OpenStudy (anonymous):

0 and –7 are solutions of the original equation. 0 is a solution of the original equation. –7 is an extraneous solution. –7 is a solution of the original equation. 0 is an extraneous solution. 7 is a solution of the original equation. 0 is an extraneous solution.

OpenStudy (jdoe0001):

if you plug in -7 to q, that is q=-7, you'd have \(\implies -7 = \sqrt{-7*-7} \implies -7 = -7\) which is correct if you plug in 0 to q, that is \(\implies -7 = \sqrt{-7*0} \implies -7 = 0\), which would make it extraneous

OpenStudy (jdoe0001):

so -7 is a solution of the original equation. 0 is an extraneous solution.

OpenStudy (jdoe0001):

wait.... shoot, not it wouldn't :(

OpenStudy (jdoe0001):

$$ \implies 0 = \sqrt{-7*0} \implies 0 = 0$$

OpenStudy (anonymous):

yes ^^ that's correct.. So is the answer still -7 is a solution of the original equation. 0 is an extraneous solution?

OpenStudy (jdoe0001):

0 and –7 are solutions of the original equation.

OpenStudy (anonymous):

oh yeah that's right lol

OpenStudy (jdoe0001):

they both yield a valid EQUATION, both factors on each side of the = sign, correlate

OpenStudy (anonymous):

\[y=4\sqrt{2x-5}= x \ge \frac{ 2 }{ 5}\]

OpenStudy (jdoe0001):

did you mean \(x\le\cfrac{5}{2}\)?

OpenStudy (jdoe0001):

\(x\ge\cfrac{5}{2}\) rather

OpenStudy (anonymous):

yes i keep messing up haha

OpenStudy (jdoe0001):

if x becomes less than that, the root becomes negative, and thus an 'imaginary' number

OpenStudy (anonymous):

wait, no i meant \[x \ge \frac{ 5 }{ 2 }\]

OpenStudy (jdoe0001):

if the DOMAIN for "x" is 5/2 and up, the RANGE is 0..\(\alpha\)

OpenStudy (anonymous):

my choices: \[x \ge \frac{ 5 }{ 2}\] \[x \ge \frac{ 2 }{ 5 }\] \[x \ge-\frac{ 5 }{ 2 }\] \[x >-\frac{ 5 }{ 2 }\]

OpenStudy (jdoe0001):

well, I guess you have the answer already then :)

OpenStudy (jdoe0001):

if x becomes \(\le\cfrac{5}{2}\) that, the root becomes negative, and thus an 'imaginary' number

OpenStudy (anonymous):

the first one right? haha just making sure ;)

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