Answer:
I'm assuming the 2 after 9t and -2t means squared.
7t² + 12t + 4
Step-by-step explanation:
To simplify the expression we should combine like terms. Like terms are terms with same variables and powers.
Let's start with 9t² and -2t² since they have the same variable and power of t². To combine them we should add them together which would be: 9t² + (-2t²) = 9t² - 2t² = 7t²
Next we can combine 7t and 5t since they have the same variable and power of t. 7t + 5t = 12t
4 doesn't have any like terms so we leave it as it is.
Lastly we add all of our terms: 7t² + 12t + 4
Answer:
Step-by-step explanation:
We are given the following in the question:
Sample size, n = 64
Sample mean = 22.3
Sample standard deviation = 8.8
We want to estimate 92% confidence interval.
92% Confidence interval:
Putting the values, we get,
Degree of freedom = n - 1 = 63
The distance, s = 40t₁ where t₁ is the time to complete the outward journey.
The same distance = vt₂ where t₂ is the time to complete the return journey at speed v.
For the whole journey, 2s=60(t₁+t₂). Therefore s=30(t₁+t₂)=40t₁=vt₂.
30t₁+30t₂=40t₁, 10t₁=30t₂, t₁=3t₂, so s=120t₂=vt₂ and v=120kph.
