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2 years ago

Using F(x) = 5x^2- 3, what is f(-3)? A. 42 B. -3 C.-48 D. -42

Mathematics

1 answer:

Gnom [1K]2 years ago

8 0

Answer: 42

Step-by-step explanation

Switch x out with 3

using Pemdas do the exponent first

3^2 is 9

then multiply

5*9= 45

then subtract

45-3=42

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find the smallest number of terms of the AP "-54,-52.5,-51,-49.5" ....that must be taken for the sum of the terms to be positive

wel

The smallest number of terms of the AP that will make the sum of terms positive is 73.

Since we need to know the number for the sum of terms, we find the sum of terms of the AP

<h3>Sum of terms of an AP</h3>

The sum of terms of an AP is given by S = n/2[2a + (n - 1)d] where

n = number of terms,
a = first term and
d = common difference

Since we have the AP "-54,-52.5,-51,-49.5" ....", the first term, a = -54 and the second term, a₂ = -52.5.

The common difference, d = a₂ - a

= -52.5 - (-54)

= -52.5 + 54

= 1.5

<h3>Number of terms for the Sum of terms to be positive</h3>

Since we require the sum of terms , S to be positive for a given number of terms, n.

So, S ≥ 0

n/2[2a + (n - 1)d] ≥ 0

So, substituting the values of the variables into the equation, we have

n/2[2(-54) + (n - 1) × 1.5] ≥ 0

n/2[-108 + 1.5n - 1.5] ≥ 0

n/2[1.5n - 109.5] ≥ 0

n[1.5n - 109.5] ≥ 0

So, n ≥ 0 or 1.5n - 109.5 ≥ 0

n ≥ 0 or 1.5n ≥ 109.5

n ≥ 0 or n ≥ 109.5/1.5

n ≥ 0 or n ≥ 73

Since n > 0, the minimum value of n is 73.

So, the smallest number of terms of the AP that will make the sum of terms positive is 73.

Learn more about sum of terms of an AP here:

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4 0

2 years ago

(x + 21)°<br> 137°<br> find the value of x.

pantera1 [17]

Answer:

x=116

Step-by-step explanation:

subtract 21 on both sides

5 0

3 years ago

An ice cream cone has height of 6 inches and a diameter of 2 inches what is the volume in cubic inches of the ice cream

GrogVix [38]

keeping in mind that radius is half the diameter, we know this cone has a diameter of 2 inches, so it has a radius of 1 inch, kinda small really for ice-cream, but anyhow.

$\textit{volume of a cone}\\\\ V=\cfrac{\pi r^2 h}{3}~~ \begin{cases} r=radius\\ h=height\\[-0.5em] \hrulefill\\ r=1\\ h=6 \end{cases}\implies V=\cfrac{\pi (1)^26}{3}\implies V=2\pi \implies \underset{\textit{rounded up}}{V\approx 6}$

5 0

2 years ago

Find the value of x<br> 6x + 12<br> 3x - 3

Shalnov [3]

Answer:

19°

Step-by-step explanation:

<u>Concept</u><u> </u><u>Used </u><u>:</u><u>-</u>

The measure of a straight line is 180°. So the sum of angles on a straight line is 180° .

Using this ,

$\bf\implies 6x + 12 + 3x - 3 = 180\\\\\bf\implies 9x + 9 = 180\\\\\bf\implies 9x = 180-9 \\\\\bf\implies x =\dfrac{171}{9} \\\\\bf\implies\boxed{\red{\bf x = 19 }}$

<h3>Hence the value of x is 19°</h3>

3 0

3 years ago

At a cell phone assembly plant, 77% of the cell phone keypads pass inspection. A random sample of 111 keypads is analyzed. Find

Serggg [28]

Answer:

The probability that the proportion of passed keypads is between 0.72 and 0.80 is 0.6677.

Step-by-step explanation:

According to the Central limit theorem, if from an unknown population large samples of sizes <em>n</em> > 30, are selected and the sample proportion for each sample is computed then the sampling distribution of sample proportion follows a Normal distribution.

The mean of this sampling distribution of sample proportion is:

$\mu_{\hat p}=p$

The standard deviation of this sampling distribution of sample proportion is:

$\sigma_{\hat p}=\sqrt{\frac{p(1-p)}{n}}$

Let <em>p</em> = the proportion of keypads that pass inspection at a cell phone assembly plant.

The probability that a randomly selected cell phone keypad passes the inspection is, <em>p</em> = 0.77.

A random sample of <em>n</em> = 111 keypads is analyzed.

Then the sampling distribution of $\hat p$ is:

$\hat p\sim N(p,\ \sqrt{\frac{p(1-p)}{n}})\\\Rightarrow \hat p\sim N (0.77, 0.04)$

Compute the probability that the proportion of passed keypads is between 0.72 and 0.80 as follows:

$P(0.72$

$=P(-1.25$

Thus, the probability that the proportion of passed keypads is between 0.72 and 0.80 is 0.6677.

8 0

3 years ago