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4 years ago

What is the value of 3ab+5b-6 when a=-1 and b=3? A.0 B.6 C.18 D.24

Mathematics

2 answers:

Otrada [13]4 years ago

5 0

Answer:

A. 0

Step-by-step explanation:

3ab+5b-6

= 3(-1)(3)+5(3)-6

=3(-3)+15-6

=-9+9

=0 ( you have to subtract because they don't have the same signs)

Mandarinka [93]4 years ago

3 0

use the substitution method

3ab+5b-6

3(-1)(3)+5(3)-6

Mutiply 3(-1)(3) first

3(-1)(3)= -3*3= -9

-9+5(3)-6

then mutiply

5(3)= 15

-9+15-6

= 6-6

= 0

Answer : A. 0

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stira [4]

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3 years ago

California University encourages professors to consider using e-textbooks instead of the traditional paper textbooks. Many cours

sergiy2304 [10]

Answer:

Step-by-step explanation:

Hello!

The variable is:

X: number of coursers taken by students during Fall 19 semester at California University that provide an e-texbook option.

The following data represents the number of courses and their point probabilities:

X: 0; 1; 2; 3; 4; 5

P(X): ? ; ?; 0.30; 0.25; 0.15; 0.10

First step is to calculate the missing point probabilities corresponding to observations X=0 and X=1

Now remember that the total sum of probabilities of a variable is 1.

So P(0) + P(1) + P(2) + P(3) + P(4) + P(5) = 1

P(0) + P(1) + 0.30 + 0.25 + 0.15 + 0.10 = 1

P(0) + P(1) + 0.80= 1

P(0) + P(1) = 1 - 0.8

P(0) + P(1) = 0.2

Now acording to the text, the probability that 1 course offers an e-book option is three times as likely as the probability of 0 courses offerig it.

If P(0)= x then P(1)= 3x, then:

x + 3x= 0.2

4x= 0.2

x= 0.2/4

x= 0.05

Wich means that P(0)= 0.05 and P(1)= 0.15, and the probability distribution for the variable is:

X: 0; 1; 2; 3; 4; 5

P(X): 0.05 ;0.15 ; 0.30; 0.25; 0.15; 0.10

F(X): 0.05; 0.2 ; 0.5 ; 0.75; 0.90; 1

The average value for this variable is:

E(X)= ∑x*P(X)= (0*0.05)+(1*0.15)+(2*0.3)+(3*0.25)+(4*0.15)+(5*0.10)= 2.6

If all courses that the university offers are above the average, the probability that all courses offer e.book options is:

P(2.6≤X≤5)= P(X≤5) - P(X<2.6)= P(X≤5) - P(X≤2)= 1 - 0.5= 0.5

I hope it helps!

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3 years ago

HELP please ASAP!!!!!

Alja [10]

Try the first one.....

3 0

4 years ago

Can someone help with my homework?

Len [333]

Answer:

1a) $-\frac{15}{4}$

1b) $\frac{95}{33}$

2a) $-84$

2b) 1

3a) $\frac{171}{550}$

3b) $4\frac{2}{7}$

Step-by-step explanation:

For the first equation, let's use $\frac{-a}{b} =\frac{a}{-b} =-\frac{a}{b}$ to right a new fraction.

Step 1- Reduce the fraction with 4.

$-\frac{\frac{12/4}{4/4} }{\frac{4}{5} } = -\frac{3}{\frac{4}{5} }$

Step 2- Simplify the complex fraction(LCD or Least Common Denominator).

$-\frac{3}{\frac{4}{5} } = -\frac{15}{4}$

An alternative form for this fraction is $-3\frac{3}{4} or -3.75$ .

For the second equation..

Step 1- Convert the mixed number to an improper fraction.

$\frac{6\frac{3}{9} }{\frac{11}{5} } = \frac{\frac{57}{9} }{\frac{11}{5} }$

Step 2- Simplify the complex fraction.

$\frac{\frac{57}{9} }{\frac{11}{5} } = \frac{95}{33}$

An alternative form for this fraction is $2\frac{29}{33} or 2.87$ .

For the third equation use $\frac{-a}{b} =\frac{a}{-b} =-\frac{a}{b}$ ...

Step 1- Simplify the complex fraction(LCD).

$-\frac{7}{\frac{1}{12} } = -84$

For the fourth equation...

Write the fraction as a division.

$\frac{12}{8}$ ÷ $\frac{3}{2}$

To divide a fraction, multiply by the reciprocal of that fraction.

$\frac{12}{8} *\frac{2}{3} = \frac{12*2}{8*3}$

Reduce the fraction with 3.

$\frac{4*2}{8}= \frac{4}{4} = 1$

For the fifth equation...

Convert the mixed number to an improper fraction.

$\frac{-1\frac{8}{11} }{-5\frac{5}{9} } = \frac{-\frac{19}{11} }{-\frac{50}{9} }$

Reduce the fraction with -1, this eliminates the negative sign.

Simplify the complex fraction.

$\frac{\frac{19}{11} }{\frac{50}{9} } = \frac{171}{550}$

An alternative form for this fraction is 0.3109.

For the sixth equation..

Write the fraction as a division.

$\frac{3}{7}$ ÷ $\frac{1}{10}$

To divide by a fraction, multiply by the reciprocal of that fraction.

$\frac{3}{7}$ ×10= $\frac{3*10}{7}$

Multiply the numbers.

$\frac{3*10}{7} = \frac{30}{7}$

Alternative form of this fraction is $4\frac{2}{7}$ or 4.285714.

Hope this helps! :)

8 0

3 years ago

What is the sum of - 1/2 and 3/4<br><br> I WILL MARK BRAINLIEST!!!

Advocard [28]

Answer:

1/4!! See ya! (Mark Brainliest)

Step-by-step explanation:

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3 years ago

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