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Alex777 [14]
3 years ago
14

(50 POINTS) Express each sum using summation notation.

Mathematics
1 answer:
vesna_86 [32]3 years ago
4 0

14: a

1

=

39

/2                              0.25               313%        16%

15:     54

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Use the Distributive Property to expand 5(3x-8y)-4
lubasha [3.4K]

Answer:

it should be 60x-160y

Step-by-step explanation:

8 0
3 years ago
Read 2 more answers
PLZ HELP I CANT GET MY PHONE UNTIL I PASS THIS TEST HELP!!!!!!!
sladkih [1.3K]

Answer:

49

Step-by-step explanation:

4 : 3

x : 21

ok so we can divide 21 by 3 and get 7.

7 × 4 = 28

4 : 3 = 28 : 21

now we just 28 + 21 = 49 :D

5 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
What is the value of the discriminant of the quadratic equation −1 = 5x2 −2x, and what does its value mean about the number of r
Zepler [3.9K]
For the equation:
-1=5 x^2 - 2 x
5 x^2 - 2 x + 1 = 0,           then we substitute: a=5,  b=-2,  c =1
to discriminant formula: D= b^2 - 4 a c = (-2)^2 - 4 * 5 * 1 = 4 - 20 = - 16
Answer:
The discriminant is equal to -16 which means the equation has no real number solutions. 
7 0
3 years ago
Read 2 more answers
Please help me with this. thank you. :)
Vinvika [58]

Answer:

11,550

Step-by-step explanation:

1200- 675( because its descending) + 250 ( its ascending) - 525 = 11,550

8 0
2 years ago
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