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2 years ago

Help pleasseeee If f(x)=3x^2-7x find f(-2)

Mathematics

1 answer:

LenKa [72]2 years ago

6 0

Answer:

f(-2) = 26

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Algebra I

Function Notation

Step-by-step explanation:

Step 1: Define

f(x) = 3x² - 7x

f(-2) is x = -2

Step 2: Evaluate

Substitute in x: f(-2) = 3(-2)² - 7(-2)
Exponents: f(-2) = 3(4) - 7(-2)
Multiply: f(-2) = 12 + 14
Add: f(-2) = 26

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Show all work and reasoning

Natalija [7]

Split up the interval [2, 5] into $n$ equally spaced subintervals, then consider the value of $f(x)$ at the right endpoint of each subinterval.

The length of the interval is $5-2=3$ , so the length of each subinterval would be $\dfrac3n$ . This means the first rectangle's height would be taken to be $x^2$ when $x=2+\dfrac3n$ , so that the height is $\left(2+\dfrac3n\right)^2$ , and its base would have length $\dfrac{3k}n$ . So the area under $x^2$ over the first subinterval is $\left(2+\dfrac3n\right)^2\dfrac3n$ .

Continuing in this fashion, the area under $x^2$ over the $k$ th subinterval is approximated by $\left(2+\dfrac{3k}n\right)^2\dfrac{3k}n$ , and so the Riemann approximation to the definite integral is

$\displaystyle\sum_{k=1}^n\left(2+\frac{3k}n\right)^2\frac{3k}n$

and its value is given exactly by taking $n\to\infty$ . So the answer is D (and the value of the integral is exactly 39).

8 0

3 years ago

Tony finishes baking cookies at 10:33 am he started at 7:18 am now long was he baking cookies?

Ber [7]

To find the amount of time between two events, we can use subtraction, just like we do with regular subtraction problems. The subtraction will look something like this:

10:33
-
7:18

Like in a regular subtraction problem, we can subtract the digits that line up, like 10 and 7. Subtracting all of the corresponding digits, we get that it took Tony 3 hours and 15 minutes to finish baking the cookies.

8 0

3 years ago

Read 2 more answers

Michael has a substantial student debt, but he recently got a new job, which came with a signing bonus. He calculates that with

MAXImum [283]

Answer:

<h2>Michael needs to save $63.40, approximately.</h2>

Step-by-step explanation:

The given expression is

$36,700 - (5,000 + 500m)=0$

Where $m$ is months.

We need to solve for the variable.

$36,700-5,000-500m=0\\31,700=500m\\m=\frac{31700}{500} \approx 63.4$

Therefore, Michael needs to save $63.40, approximately.

4 0

3 years ago

Read 2 more answers

ANY EXAPLE OF DISTRIBUTIVE PROPERTY FAST!!!

vivado [14]

Answer:

My example: 7(2 + 7) = 7(2) + 7(7)

Formula: x(y + x) = x*y + x*x

Step-by-step explanation:

The distributive property can be represented by the following equation:

x(y + x) = x*y + x*x

Since you are looking for any example, let's plug in a few numbers to the above equation.

Ex) x = 7, y = 2

The example equation with these values is 7(2 + 7)

Solving With Distributive Property:

x(y + x)

Substitute

7(2 + 7)

Simplify using distributive property

7(2) + 7(7)

14 + 49 = 63

Solving using PEMDAS and solving inside the parenthesis first

7(2 + 7)

7(9)

The above is an example of solving/siplifying equations with and without the Distributive Property.

Since these numbers are the same, we can conclude that the formula for the distributive property above is correct.

Again, you are looking for an example, so simply pick a value for x and y and substute into this equation: x(y + x) = x*y + x*x

I used 7 and 2 above, but any numbers will work as you are distributing the value outside the parenthesis.

Hope this helps! Let me know if you have any questions.

PEMDAS simpliy means that the solving of equations can be solved by going in the following order:

- Parenthesis (P)

- Exponents (E)

- Multiplication and Division left to right of the expression/equation (M/D)

- Addition and Subtraction (A/S)

This is just a helpful little refrence when applying the order of operations.

6 0

3 years ago

In January 2002, two students made worldwide headlines by spinning a Belgian euro 250 times and getting 140 heads—that’s 56%. Th

natita [175]

Answer with explanation:

The 90% confidence interval (51%, 61%) for proportion means that the proportion of getting heads lie in it.

Given : Total number of times coin is tossed = 250

Number of times they got head =140

The probability of getting a head = 0.56

The confidence interval for proportion is given by :-

$p\pm z_{\alpha/2}\sqrt{\dfrac{p(1-p)}{n}}$

Given significance level : $\alpha=1-0.90=0.1$

Critical value : $z_{\alpha/2}=z_{0.05}=\pm1.645$

Now, the 90% confidence interval for proportion will be :-

$0.56\pm (1.645)\sqrt{\dfrac{0.56(1-0.56)}{250}}\approx0.56\pm 0.0516\\\\=(0.56-0.0516,0.56+0.0516)=(0.5084,\ 0.6116)\approx(51\%,\ 61\%)$

Hence, the given confidence interval is correct.

6 0

2 years ago