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4 years ago

11

If B = -m +1 - 9m2 and A = m + 9, find an expression that equals 2B – 2A

1 answer:

photoshop1234 [79]4 years ago

5 0

Answer:

- 18m² - 4m - 16

Step-by-step explanation:

2B - 2A

= 2(- m + 1 - 9m²) - 2(m + 9) ← distribute both parenthesis

= - 2m + 2 - 18m² - 2m - 18 ← collect like terms

= - 18m² - 4m - 16 ← in standard form

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What is another number of pennies and total mass of pennies in grams if my number of pennies is 10 and the mass in grams is 25

Angelina_Jolie [31]

Answer:

1 penny is equal to 2.5 grams

Step-by-step explanation:

1 penny = 2.5 grams

2 pennies = 5.0 grams

3 pennies = 7.5 grams

Just add 2.5 grams every penny.

Pick any number of pennies and multiply it by 2.5 (Don't forget to add grams ( g ) at the end.

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3 years ago

What is the absolute value of 1/2?

harina [27]

The Absolute Value of a number is "the magnitude of a real number without regard to its sign". So the Absoulute Value of 1/2 is |1/2|

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3 years ago

Solve each system of equations (systems with 3 variables)

Natasha2012 [34]

Answer:

x = 2 , y = 5 , z = -1 You are correct!!!

Step-by-step explanation:

Solve the following system:

{9 x + 3 y - 4 z = 37 | (equation 1)

4 x + 3 y + 7 z = 16 | (equation 2)

x - 5 y + 8 z = -31 | (equation 3)

Subtract 4/9 × (equation 1) from equation 2:

{9 x + 3 y - 4 z = 37 | (equation 1)

0 x+(5 y)/3 + (79 z)/9 = (-4)/9 | (equation 2)

x - 5 y + 8 z = -31 | (equation 3)

Multiply equation 2 by 9:

{9 x + 3 y - 4 z = 37 | (equation 1)

0 x+15 y + 79 z = -4 | (equation 2)

x - 5 y + 8 z = -31 | (equation 3)

Subtract 1/9 × (equation 1) from equation 3:

{9 x + 3 y - 4 z = 37 | (equation 1)

0 x+15 y + 79 z = -4 | (equation 2)

0 x - (16 y)/3 + (76 z)/9 = (-316)/9 | (equation 3)

Multiply equation 3 by 9/4:

{9 x + 3 y - 4 z = 37 | (equation 1)

0 x+15 y + 79 z = -4 | (equation 2)

0 x - 12 y + 19 z = -79 | (equation 3)

Add 4/5 × (equation 2) to equation 3:

{9 x + 3 y - 4 z = 37 | (equation 1)

0 x+15 y + 79 z = -4 | (equation 2)

0 x+0 y+(411 z)/5 = (-411)/5 | (equation 3)

Multiply equation 3 by 5/411:

{9 x + 3 y - 4 z = 37 | (equation 1)

0 x+15 y + 79 z = -4 | (equation 2)

0 x+0 y+z = -1 | (equation 3)

Subtract 79 × (equation 3) from equation 2:

{9 x + 3 y - 4 z = 37 | (equation 1)

0 x+15 y+0 z = 75 | (equation 2)

0 x+0 y+z = -1 | (equation 3)

Divide equation 2 by 15:

{9 x + 3 y - 4 z = 37 | (equation 1)

0 x+y+0 z = 5 | (equation 2)

0 x+0 y+z = -1 | (equation 3)

Subtract 3 × (equation 2) from equation 1:

{9 x + 0 y - 4 z = 22 | (equation 1)

0 x+y+0 z = 5 | (equation 2)

0 x+0 y+z = -1 | (equation 3)

Add 4 × (equation 3) to equation 1:

{9 x+0 y+0 z = 18 | (equation 1)

0 x+y+0 z = 5 | (equation 2)

0 x+0 y+z = -1 | (equation 3)

Divide equation 1 by 9:

{x+0 y+0 z = 2 | (equation 1)

0 x+y+0 z = 5 | (equation 2)

0 x+0 y+z = -1 | (equation 3)

Collect results:

Answer: {x = 2 , y = 5 , z = -1

5 0

3 years ago

A national consumer agency selected independent random samples of 45 owners of newer cars (less than five years old) and 40 owne

Igoryamba

Answer:

(195 - 286) ± 1.992 * sqrt((46^2/45) + (58^2/40))

Step-by-step explanation:

Given that:

NEWER CARS:

Sample size = n1 = 45

Standard deviation s1 = 46

Mean = m1 = 195

OLDER CARS:

Sample size = n2 = 40

Standard DEVIATION s2 = 58

Mean = m2 = 286

Confidence interval at 95% ; α = 1 - 0.95 = 0.05 ; 0.05 / 2 = 0.025

Confidence interval is calculated thus : (newer--older)

(m1 - m2) ± Tcritical * standard error

Mean difference = m1 - m2; (195 - 286)

Tcritical = Tn1+n2-2, α/2 = T(45+40)-2 = T83, 0.025 = 1.99 (T value calculator)

Standard error (E) = sqrt((s1²/n1) + (s2²/n2))

E = sqrt((46^2/45) + (58^2/40))

Hence, confidence interval:

(195 - 286) ± 1.992 * sqrt((46^2/45) + (58^2/40))

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3 years ago

What is the value of tan M?

Lelu [443]

Answer:

The value of tan M = 15/8

Step-by-step explanation:

$tan \: m \: = \frac{p}{b} \\ tan \: m \: = \frac{15}{8}$

5 0

2 years ago