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# Isolating quantities — Harder example

Watch Sal work through a harder Isolating quantities problem.

## Want to join the conversation?

• At , can't we just raise 1 and r to the power of t?
that would mean:
1+r^t=A/P (Since 1^anything = 1)
therefore:
r^t=(A/P) - 1
giving:
r=((A/P)-1)

Just a question. I may be wrong but I think I need some clarification here.
• you know the formula for (a+b)^2,,,right
It contains a 2ab term
similarly ,a cubic equation contains a 3ab(a+b) term
Therefore,it's reasonable to infer that anything to the power of t would not contain isolated exponential sum of the individual terms.
Hope it helps :)
• At 1;20, why do you need to raise t to the 1 over t power?
• From the author:Great question! Sal is using a common method to simplify radical expressions. For example, if you have x^3 = 27, then you can take the cube root of both sides of the equation to solve for x. If you have learned about fractional exponents, remember that taking the cube root of something is the same as raising it to the (1/3) power. Similarly, taking the square root of something is the same as raising it to the (1/2) power. So, to cancel out the t power, Sal is raising both sides of the equation to the *(1/t)* power.
• tbh, i like this kinda isolating quantities problems. <3
• any other videos explaining this type of math? I have no idea whats going on
• Hi all, wish you guys luck.
• my teachers taught me a whole different way to do the problem dealing with isolating quantities harder example. can someone please confirm what the recommended way to do this is?
(1 vote)
• Well, what way did your teacher teach you? Just use the one you're comfortable with.
• Isn't one raised to any power 1? So why couldn't the answer be c?