Answer:
B
The answer is B, which is -1.5.
a.
The polynomial w^2+18w+84 cannot be factored
The perfect square trinomial is w^2+18w + 81
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The reason the original can't be factored is that solving w^2+18w+84=0 leads to no real solutions. Use the quadratic formula to see this. The graph of y = x^2+18x+84 shows there are no x intercepts. A solution and an x intercept are basically the same. The x intercept visually represents the solution.
w^2+18w+81 factors to (w+9)^2 which is the same as (w+9)(w+9). We can note that w^2+18w+81 is in the form a^2+2ab+b^2 with a = w and b = 9
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b.
The polynomial y^2-10y+23 cannot be factored
The perfect square trinomial is y^2-10y + 25
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Using the quadratic formula, y^2-10y+23 = 0 has no rational solutions. The two irrational solutions mean that we can't factor over the rationals. Put another way, there are no two whole numbers such that they multiply to 23 and add to -10 at the same time.
If we want to complete the square for y^2-10y, we take half of the -10 to get -5, then square this to get 25. Therefore, y^2-10y+25 is a perfect square and it factors to (y-5)^2 or (y-5)(y-5)
Answer:
n = -7
Step-by-step explanation:
Solve for n:
-3 n - 5 = 16
Hint: | Isolate terms with n to the left-hand side.
Add 5 to both sides:
(5 - 5) - 3 n = 5 + 16
Hint: | Look for the difference of two identical terms.
5 - 5 = 0:
-3 n = 16 + 5
Hint: | Evaluate 16 + 5.
16 + 5 = 21:
-3 n = 21
Hint: | Divide both sides by a constant to simplify the equation.
Divide both sides of -3 n = 21 by -3:
(-3 n)/(-3) = 21/(-3)
Hint: | Any nonzero number divided by itself is one.
(-3)/(-3) = 1:
n = 21/(-3)
Hint: | Reduce 21/(-3) to lowest terms. Start by finding the GCD of 21 and -3.
The gcd of 21 and -3 is 3, so 21/(-3) = (3×7)/(3 (-1)) = 3/3×7/(-1) = 7/(-1):
n = 7/(-1)
Hint: | Simplify the sign of 7/(-1).
Multiply numerator and denominator of 7/(-1) by -1:
Answer: n = -7
This exponential growth/decay (in this case decay because r<1) of the form:
f=ir^t, f=final value, i=initial value, r=common ratio or "rate", t=time.
Since the population decreases by 4.5% each year the common ratio is:
r=(100-4.5)/100=0.955 so we can say
P(t)=8500(0.955^t)
....
7000=8500(0.955^t)
14/17=(955/1000)^t taking the natural log of both sides
ln(14/17)=t ln(955/1000)
t=ln(14/17)/ln(955/1000)
t≈4.22 years (to nearest hundredth of a year)
Since t is the years since 2010, the population will fall to 7000 in the year (2010+4.22=2014.22, more than four years will have elapsed) 2015.
Answer:
Step-by-step explanation:
just find a new photo
