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4 years ago

42 is 21% of what number?

Mathematics

2 answers:

Margarita [4]4 years ago

8 0

42 is 21% of 200. This is because 200*0.21 = 42.

Soloha48 [4]4 years ago

7 0

21n/100=42

21n=4200

n=200

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If you can buy 1/3 of a box of chocolates for 6 dollars how much can you purchase for 4 dollars?

sladkih [1.3K]

$You \: can \: purchase :4 \times \frac{1}{3} \div 6 = \frac{2}{9} \: of \: a \: box$

5 0

4 years ago

1/4+1/2 find the sum using number line

Arte-miy333 [17]

It's 3/4

no number line provided for me, but if you find the common denominator (4), and convert 1/2 into 2/4, then adding 2/4+1/4 is easy, and equals 3/4

3 0

4 years ago

What is this answer (2)(−5)(−5)

Amiraneli [1.4K]

Answer:

Step-by-step explanation:

(-5)* (-5) = 25; as the negatives cancel out

25 * (2) = 50; arithmetic

6 0

2 years ago

Read 2 more answers

Find all possible values of b such that 4x² + bx + 3 can be factored. Check all that apply.

aleksklad [387]

The possible values of b are 7 and 8

<h3>How to determine the possible values of x?</h3>

The expression is given as:

4x² + bx + 3

Next, we test the options to determine the values of b

<u>Option 1: b = 13</u>

So, we have:

4x² + 13x + 3 ---- this cannot be factorized

<u>Option 2: b = 7</u>

So, we have:

4x² + 7x + 3

Expand

4x² + 4x + 3x + 3

Factorize

4x(x +1) + 3(x + 1)

Factor out x + 1

(4x + 3)(x + 1) ------ this can be factorized

<u>Option 3: b = 8</u>

So, we have:

4x² + 8x + 3

Expand

4x² + 6x + 2x + 3

Factorize

2x(2x +3) + 1(2x + 3)

Factor out 2x + 3

(2x + 3)(2x + 1) ------ this can be factorized

<u>Option 4: b = 1</u>

So, we have:

4x² + x + 3 ---- this cannot be factorized

Hence, the possible values of b are 7 and 8

Read more about factorized expressions at:

brainly.com/question/723406

#SPJ1

3 0

2 years ago

First make a substitution and then use integration by parts to evaluate the integral. (Use C for the constant of integration.) x

e-lub [12.9K]

Answer:

$(\frac{x^{2}-25}{2})ln(5+x)-\frac{x^{2}}{4}+\frac{5x}{2}+C$

Step-by-step explanation:

Ok, so we start by setting the integral up. The integral we need to solve is:

$\int x ln(5+x)dx$

so according to the instructions of the problem, we need to start by using some substitution. The substitution will be done as follows:

U=5+x

du=dx

x=U-5

so when substituting the integral will look like this:

$\int (U-5) ln(U)dU$

now we can go ahead and integrate by parts, remember the integration by parts formula looks like this:

$\int (pq')=pq-\int qp'$

so we must define p, q, p' and q':

p=ln U

$p'=\frac{1}{U}dU$

$q=\frac{U^{2}}{2}-5U$

q'=U-5

and now we plug these into the formula:

$\int (U-5)lnUdU=(\frac{U^{2}}{2}-5U)lnU-\int \frac{\frac{U^{2}}{2}-5U}{U}dU$

Which simplifies to:

$\int (U-5)lnUdU=(\frac{U^{2}}{2}-5U)lnU-\int (\frac{U}{2}-5)dU$

Which solves to:

$\int (U-5)lnUdU=(\frac{U^{2}}{2}-5U)lnU-\frac{U^{2}}{4}+5U+C$

so we can substitute U back, so we get:

$\int xln(x+5)dU=(\frac{(x+5)^{2}}{2}-5(x+5))ln(x+5)-\frac{(x+5)^{2}}{4}+5(x+5)+C$

and now we can simplify:

$\int xln(x+5)dU=(\frac{x^{2}}{2}+5x+\frac{25}{2}-25-5x)ln(5+x)-\frac{x^{2}+10x+25}{4}+25+5x+C$

$\int xln(x+5)dU=(\frac{x^{2}-25}{2})ln(5+x)-\frac{x^{2}}{4}-\frac{5x}{2}-\frac{25}{4}+25+5x+C$

$\int xln(x+5)dU=(\frac{x^{2}-25}{2})ln(5+x)-\frac{x^{2}}{4}+\frac{5x}{2}+C$

notice how all the constants were combined into one big constant C.

7 0

3 years ago