I have the answers .. but can someone explain how to get them? Thank you xx
So you have to solve for \(x\) then?
d. x=1.69 e.x=3.68 f. x=42.88 g. x=32 h. x=18.99 i=58.72
yes the directions say to solve for x
You have to change the expression into a simple fractional exponent. Something of the form \(x^{a/b}\). Then you take both sides to the power of \(b/a\). This will isolate \(x\).
for example for d what would I raise?
For \(d\), we can see \[ \frac{1}{\sqrt{x}} = \frac{1}{x^{1/2}}=x^{-1/2} \]Now the reciprocal of \(-1/2\) is going to be \(-2/1 = -2\).
Thus \[ \left(\frac{1}{\sqrt{x}}\right)^{-2}=x=(0.77)^{-2} \]
ok I see now :) thanks so much so for e what would i have to do since theres 8 in the root
Use \[ \sqrt[b]{x^a} = x^{a/b} \]
Remember that \(\sqrt{x} = \sqrt[2]{x}\)
You also need to use \(\frac{1}{x^a}=x^{-a}\)
so -2/3?
Well, there is no negative in d.
whoops, I mean no negative in e. We had one in d because it was a fraction.
I don't really understand how to do e. I looked at the rules but I didn't understand :/
Okay for e, we have to do it one at a time.
\[ \sqrt{8x^3}=(8x^3)^{1/2} \]So first we do both sides to the power of \(2\).
\[ 8x^3 = (20)^2 = 400 \]
Then we divide by \(8\): \[ x^3= 400/8=50 \]
Now we do reciprocal of \(3\) which is \(1/3\) \[ x = (50)^{1/3} \]
oh ok i see now:))) so for f-i are they the same method?
Yes.
When you isolate the variable, you generally get rid of things opposite of the order of operations. Thus exponents are the last part to get rid of.
for f is would be 1/3 since we don't touch the exponent?
What do you mean?
because i think you would need to subtract 18 and 32 -18 is 14 so i'm kinda stuck from there
Yes, then you get rid of the \(4\) next.
Then you can get rid of the power after that.
to get rid of the 4 can i just divide it or do i do the reciprocal?
You are dividing. Which is actually the same as multiplying by the reciprocal.
You can divide by \(4\) or multiply by \(1/4\). Both work.
how would the power of 3 work though
Well, you have \(x^{1/3}\). The reciprocal is \(3\).
but 14 to the exponent of 1/3 isn't 42.88 that's where i'm kinda lost
it's just the 1/4 and the 1/3 are confusing me
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lool
does anyone know how to do f? I'm seriously stuck
\[4\sqrt[3]{x}+18=32\]Subtract 18 from both sides.\[4\sqrt[3]{x}=14\]Divide both sides by 4.\[\sqrt[3]{x}=\frac{7}{2}\]Raise both sides to the 3rd power.\[x=(\frac{7}{2})^3 \]
Or if you prefer: \[4\sqrt[3]{x} = 14\]Raise both sides to 3rd power.\[64x=2744\]\[x=\frac{343}{8}\]
thank you so much for helping everything.. I really appreciate it!
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