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3 years ago

I need help Please!

Mathematics

2 answers:

goldenfox [79]3 years ago

8 0

Answer:

To solve, use a simple one-step equation

Known: Number of coins; Number of Nickles.

Unknown: Number of Dimes.

a) To find the number of Dimes

b) Use x (or virtually any letter) to represent the unknown number of dimes

c) 9+x=13

d) Subtract 9 from both sides to cancel out the 9 and isolate the variable on one side. x=4

e) 9+4=13, so yes, the answer is correct

Jet001 [13]3 years ago

7 0

A. How many dimes is there out of the 13 coins.
B. D= dimes
C. 9+d=13
D. 9+d=13
Subtract 9 from 13
13-9=4
D=4
9+4=13

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4vir4ik [10]

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3 years ago

- Mona Allen wants to buy a bed that costs $695. The city sales tax rate is 7%. In a nearby city the sales tax rate is 4%. How m

pentagon [3]

Answer:

$20.85 less.

Step-by-step explanation:

City sales:

7% tax = 48.65

total bed cost = $743.65

Nearby City:

4% tax = 27.8

total bed cost = $722.8

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3 0

3 years ago

Find the integral using substitution or a formula.

Nadusha1986 [10]

$\rm \int \dfrac{x^2+7}{x^2+2x+5}~dx$

Derivative of the denominator:
$\rm (x^2+2x+5)'=2x+2$

Hmm our numerator is 2x+7. Ok this let's us know that a simple u-substitution is NOT going to work. But let's apply some clever Algebra to the numerator splitting it up into two separate fractions. Split the +7 into +2 and +5.

$\rm \int \dfrac{x^2+2+5}{x^2+2x+5}~dx$

and then split the fraction,

$\rm \int \dfrac{x^2+2}{x^2+2x+5}~dx+\int\dfrac{5}{x^2+2x+5}~dx$

Based on our previous test, we know that a simple substitution will work for the first integral: $\rm \quad u=x^2+2x+5\qquad\to\qquad du=2x+2~dx$

So the first integral changes,

$\rm \int \dfrac{1}{u}~du+\int\dfrac{5}{x^2+2x+5}~dx$

integrating to a log,

$\rm ln|x^2+2x+5|+\int\dfrac{5}{x^2+2x+5}~dx$

Other one is a little tricky. We'll need to complete the square on the denominator. After that it will look very similar to our arctangent integral so perhaps we can just match it up to the identity.

$\rm x^2+2x+5=(x^2+2x+1)+4=(x+1)^2+2^2$

So we have this going on,

$\rm ln|x^2+2x+5|+\int\dfrac{5}{(x+1)^2+2^2}~dx$

Let's factor the 5 out of the intergral,
and the 4 from the denominator,

$\rm ln|x^2+2x+5|+\frac54\int\dfrac{1}{\frac{(x+1)^2}{2^2}+1}~dx$

Bringing all that stuff together as a single square,

$\rm ln|x^2+2x+5|+\frac54\int\dfrac{1}{\left(\dfrac{x+1}{2}\right)^2+1}~dx$

Making the substitution: $\rm \quad u=\dfrac{x+1}{2}\qquad\to\qquad 2du=dx$

giving us,

$\rm ln|x^2+2x+5|+\frac54\int\dfrac{1}{\left(u\right)^2+1}~2du$

simplying a lil bit,

$\rm ln|x^2+2x+5|+\frac52\int\dfrac{1}{u^2+1}~du$

and hopefully from this point you recognize your arctangent integral,

$\rm ln|x^2+2x+5|+\frac52arctan(u)$

undo your substitution as a final step,
and include a constant of integration,

$\rm ln|x^2+2x+5|+\frac52arctan\left(\frac{x+1}{2}\right)+c$

Hope that helps!
Lemme know if any steps were too confusing.

8 0

3 years ago

Need help with this geometry problem hard for me smart people only 100% pls fast due now

34kurt

Answer:

x = 30°

Step-by-step explanation:

We know that the sum of all of the interior angles of a triangle is 180°, therefore, we can write the following equation:

x + 2x + 3x = 180

6x = 180

x = 30°

8 0

3 years ago

Out of 160 workers surveyed at a company, 37 walk to work.

Sonja [21]

A. 37/100
b. 736. 3300/160 is 20.215
20.215x37 =
736. hope this helped

5 0

3 years ago