Ask question

Ask question

All categories

3 years ago

7

Completely factor 6a^2 - 8a - 30

1 answer:

pychu [463]3 years ago

4 0

Factor out 2
2(3a^2-4a-15)
hmm
trial and error
nope
fancy I-forgot-the-name way
multiply 3 and -15 to get -45
find y and t such that yt=-45 and y+t=-4
tricky
hmm
-9 and 5
split -4a into -9a and 5a
2(3a^2-9a+5a-15)
split and factor
2[(3a^2-9a)+(5a-15)]
factor oout common factors
2[3a(a-3)+5(a-3)]
epic reverse distribute, remmber ab+ac=a(b+c) the (a-3) is theh a part
2[(a-3)(3a+5)]
something
(2)(a-3)(3a+5)
(2)(3a+5)(a-3) is factored form

You might be interested in

Suppose X and Y are random variables with joint density function. f(x, y) = 0.1e−(0.5x + 0.2y) if x ≥ 0, y ≥ 0 0 otherwise (a) I

Hatshy [7]

a. $f_{X,Y}$ is a joint density function if its integral over the given support is 1:

$\displaystyle\int_{-\infty}^\infty\int_{-\infty}^\infty f_{X,Y}(x,y)\,\mathrm dx\,\mathrm dy=\frac1{10}\int_0^\infty\int_0^\infty e^{-x/2-y/5}\,\mathrm dx\,\mathrm dy$

$=\displaystyle\frac1{10}\left(\int_0^\infty e^{-x/2}\,\mathrm dx\right)\left(\int_0^\infty e^{-y/5}\,\mathrm dy\right)=\frac1{10}\cdot2\cdot5=1$

so the answer is yes.

b. We should first find the density of the marginal distribution, $f_Y(y)$ :

$f_Y(y)=\displaystyle\int_{-\infty}^\infty f_{X,Y}(x,y)\,\mathrm dx=\frac1{10}\int_0^\infty e^{-x/2-y/5}\,\mathrm dy$

$f_Y(y)=\begin{cases}\dfrac15e^{-y/5}&\text{for }y\ge0\\\\0&\text{otherwise}\end{cases}$

Then

$P(Y\ge8)=\displaystyle\int_8^\infty f_Y(y)\,\mathrm dy=e^{-8/5}$

or about 0.2019.

For the other probability, we can use the joint PDF directly:

$P(X\le5,Y\le8)=\displaystyle\int_0^5\int_0^8f_{X,Y}(x,y)\,\mathrm dx\,\mathrm dy=1+e^{-41/10}-e^{-5/2}-e^{-8/5}$

which is about 0.7326.

c. We already know the PDF for $Y$ , so we just integrate:

$E[Y]=\displaystyle\int_{-\infty}^\infty y\,f_Y(y)\,\mathrm dy=\frac15\int_0^\infty ye^{-y/5}\,\mathrm dy=\boxed5$

5 0

3 years ago

Hey There! i need ur help Please!!!!

Amiraneli [1.4K]

Answer:

35 5x7=35

Step-by-step explanation:)

35 $hope you love it$

5 0

3 years ago

Need help plz<br>I'm horrible at math

Ludmilka [50]

For number 2, like i said in the comments, is 20 hours.

8/12*30

For number three, the answer is 38 Ibs on Mars.

4/10 = x/95

4*95/10= x

X= 380/10 which equals 38.

For 4, the answer is 48 oz of pineapple juice.

3 x 64/4 which equals to 48.

For 5, you will need 6 cups of flour.

Hope this helps & good luck. :)

4 0

4 years ago

The sum<br> of two numbers is 72. The difference is<br> 22. Find the two numbers.

kotegsom [21]

Answer:

b= 25

Step-by-step explanation:

a+b =72

a-b = 22

2a = 94

DBS(Divide Both Side) by 2

a = 47

=47 +b =72

and:

47 -b =22

subtract 47 from both sides:

b=25

and

-b = -25 MBS(Multiply Both Side) by-1 ....>b=25

5 0

3 years ago

Phantasy [73]

Answer:

1/2

Step-by-step explanation:

6 0

3 years ago