9514 1404 393
Explanation:
The problem statement tells you the meaning of t. It is minutes after Riko leaves. 0 ≤ t < 52.5 is the answer to the question regarding the interval Riko is behind Yuto. It means Riko is behind Yuto for 52.5 minutes after she leaves their house.
t will not be negative because time moves forward. Here, we're only counting time <em>after Riko leaves the house</em>. A negative value for t would refer to a time before Riko leaves the house, which is irrelevant in this problem.*
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* One might argue that Riko is behind Yuto for all values of time <em>after Yuto leaves the house</em>, which would be for -21 < t < 52.5. The concept of "behind Yuto" has no meaning except in that interval.
{y | y>9}, because the graph starts at 9, thus the y-values must be greater than 9
Given equation is : ![x^{2}-4=0](https://tex.z-dn.net/?f=x%5E%7B2%7D-4%3D0)
Solving it we get,
![x^{2}=4](https://tex.z-dn.net/?f=x%5E%7B2%7D%3D4)
and ![\sqrt{x}=-\sqrt{4}](https://tex.z-dn.net/?f=%5Csqrt%7Bx%7D%3D-%5Csqrt%7B4%7D)
This gives
and
or we can say the roots are ![(x+2)(x-2)](https://tex.z-dn.net/?f=%28x%2B2%29%28x-2%29)
Here Stefan is right, the root has a multiplicity of 1.
12t +9
because you basically just take w of t and plug in 3t for t itself. This means you end up with 3(4t+3) and you evenly distribute, unless you want to simplify further you could maybe take it to 4t+3 but it just depends on the math youre doing. If you're taking calculus then you should be fine with the above answer since, you dont need to further simplify once you take the exam at the very end of your course. Hope this helps :)