I'll guess the answer is <em>you can tell that pi is an irrational because it has a </em>non-terminating yet non-repeating decimal representation.<em>
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Of course it's not clear how we tell this. We can't know for sure just by looking at the first trillion digits we've figured out whether it repeats or not. Someone told us it didn't, that's really how we know.
Your answer for rounding 2.8497 x 10^3 is correct: 2.85 x 10^3.
350.0 is not correct because it has 4 sig figs. The proper rounding would be simply 350. with not additional zeros.
The rate of change is -6 because it’s being subtracted by 6 each time.
8n+3+9n+7=180
17n+10=180
17n=170
Answer
N=10
Answer:
x ∈ {-5, -1}
Step-by-step explanation:
Here's the solution using the quadratic formula:

The real zeros are -5 and -1.
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There are many ways to check your answer. One of them is to look at the given quadratic, which has no changes of sign in its coefficients. (They are all positive.) That means there can be no positive real roots, so already you know that x=0.5 won't work.
Also, the constant in the quadratic is the product of the roots, For your roots, their product is -7/4, so even multiplying by 4 (the leading coefficient in the given quadratic), you don't get anything like 20.