Answer:
Step-by-step explanation:
In order to determine the information you're being asked for, you need to complete the square on that quadratic. The first step is to move the constant over to the other side of the equals sign:

Here would be the step where, if the leading coefficient isn't a 1, you'd factor it out. But ours is a 1, so we're good there. Now take half the linear term (the term with the single x on it), square it, and add it to both sides. Our linear term is a -2. Half of -2 is -1, and -1 squared is +1. We add +1 to both sides giving us this:

Now we'll clean it up a bit. The right side becomes a 4, and the left side is written as its perfect square binomial, which is the whole reason we did this. That binomial is
(set equal to the 4 here). Now we'll move the 4 back over and set the whole thing back equal to y:

From this it's apparent what the vertex is: (1, -4),
the axis of symmetry is x = 1, and
the y-intercept is found by setting the x's equal to 0 in the original equation and solving for y. So the y-intercept is (0, -3).
Your choice for the correct answer is the very last one there.
Answer:
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Explanation:
Simulate (build a table) the growing of the number of pennies for some nights to figure out the pattern:
First night: 1 penny = 2⁰
Second night: 1 × 2 pennies = 2¹
Third night: 2 × 2 = 2²
Fourth nigth: 2² × 2 = 2³
nth night: 2ⁿ⁻¹
You want 2ⁿ⁻¹ ≥ 2,000,000,000
Which you solve in this way:
- n-1 log (2) ≥ log (2,000,000,000)
- n - 1 ≥ log (2,000,000,000) / log (2)
Since n is number of days, it is an integer number, so n ≥ 32.
Hence, she will have a total of more than $ 2 billion after 32 days.
You can prove that by calculating 2³² = 2,147,483,648.
Answer:
A+3B=4+5r
Step-by-step explanation:
Given that,
A = 1+r+7r
B = 1-r
We need to find an expression that is equal to A+3B.
Putting the values of A and B in A+3B, we get :
A+3B = 1+r+7r + 3(1-r)
=1+8r+3-3r
=(1+3) +(8r-3r)
=4+5r
Hence, the values of A+3B equals 4+5r.