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3 years ago

Which expression is equivalent to 4 -(-7)? A 7+4, B 4-7, C -7-4, D -4+7

1 answer:

8 0

Hi there! You are subtracting a negative number, which is basically the same thing as adding, because two negatives make a positive. B and C is out, because they do not fit the expression. You are actually adding both numbers and anytime you have to subtract a negative number, you add. When you do basic math, 4 + 7 is 11. Both numbers are negative and D does not work, because you're adding from a negative number. The only answer choice that has the expression is A. The answer is A.

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Ryan works mowing lawns and babysitting. He earns $8.20 an hour for mowing and $7.70 an hour for babysitting. How much will he e

Snezhnost [94]

Answer:

Step-by-step explanation:

Ryan works mowing lawns and babysitting. He earns $8.20 an hour for mowing and $7.70 an hour for babysitting. Therefore, the expression for the total amount that he would earn if he mows lawns for x hours and babysits for y hours would be

8.2x + 7.7y

Therefore, the amount that he would earn for 3 hours of mowing and 7hours of babysitting is

(8.2 × 3) + (7.7 × 7)

= 24.8 + 53.9

= $78.7

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2 years ago

Question 2 An exponential model y = a.6 passes through the points (0,9) and (3,243). What are the values of a and b?

weqwewe [10]

Answer:

a = 9, b = 3

Step-by-step explanation:

The exponential function is

y = a $b^{x}$

Find a and b by using the points it passes through

Using (0, 9 ) then

9 = a $b^{0}$ ( $b^{0}$ = 1 )

a = 9

y = 9 $b^{x}$

Using (3, 243 ) then

243 = 9b³ ( divide both sides by 9 )

27 = b³ ( take the cube root of both sides )

b = $\sqrt[3]{27}$ = 3

y = 9 $(3)^{x}$ ← exponential equation

8 0

2 years ago

The following piecewise function gives the tax owed, T(x), by a single taxpayer on a taxable income of x dollars.  T(x) = (i) De

Luda [366]

(i) To show that a piecewise function is continuous at a point, we need to show that the left hand and right hand limit "agree" with each other. In other words, we want:

$\lim_{x\to 6061^-} T(x) = \lim_{x \to 6061^+} T(x)$

Now, since we're given the constraints and the equation of each constraint, we notice that 6061^+ is a number that is slightly bigger than 6061. So we use the second equation. Do you see why?

In much the same way, 6061^- is a number that is slightly smaller than 6061. So we use the first equation. Again, do you see why? (Hint: look at the conditions on x for each equation).

So finally, computing each limit means just "plugging" 6061 into their respective equations. That is:

$\lim_{x \to 6061^-} T(x) = 0.10\times 6061 = 606.1$

$\lim_{x \to 6061^+} T(x) = 606.1 + 0.18(6061 - 6061) = 606.1$

Since your limits match, we say that, at the point x = 6061, T(x) IS continuous.

(ii) Repeat the process above with x = 32473.

(iii) Find a point of discontinuity just means your right hand and left hand limits do not match -- I'm not an economist, so I may not be of much help with the latter part of the question!

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3 years ago

Read 2 more answers

The fractions bars are 1/6 2/6 4/6 and 1/3

Snezhnost [94]

Do we need to add them?

What are we doing with this information?

5 0

3 years ago

In a certain school, 6% of all students get a probation due to diverse reasons. Use the Poisson approximation to the binomial di

photoshop1234 [79]

Answer:

Step-by-step explanation:

In a certain school, 6% of all students get a probation due to diverse reasons. This means that

p = 6/100 = 0.06

Number of randomly selected students is 80. This means that

n = 80

Mean, u = np = 80×0.06 = 4.8

Using poisson probability distribution,

P(x=r) = (e^-u × u^r)/r!

a) 4 will get at least one probation in any given year. It becomes

P(x=4) = (e^-4.8 × 4.8^4)/4! = 0.18

b) At least 3 will get at least one probation in any given year. This means

P(x greater than or equal to 3) = 1 - P(x lesser than or equal to 2)

P(x lesser than or equal to 2) = P(x = 0) + P(x = 1) +/P(x = 2)

P(x = 0) = (e^-4.8 × 4.8^0)/0! = 0.0082

P(x = 1) = (e^-4.8 × 4.8^1)/1! = 0.04

P(x = 2) = (e^-4.8 × 4.8^2)/2! = 0.38

P(x lesser than or equal to 2) = 0.0082 + 0.04 + 0.38 = 0.4282

c) Anywhere from 3 to 6, inclusive will get at least one probation in any given year. This means

P( 3 lesser than or equal to x lesser than or equal to 6) = P(x = 3) + P(x = 4) + P(x = 5) + P(x = 6)

P(x = 3) = (e^-4.8 × 4.8^3)/3! = 0.15

P(x = 4) = (e^-4.8 × 4.8^4)/4! = 0.18

P(x = 5) = (e^-4.8 × 4.8^5)/5! = 0.17

P(x = 5) = (e^-4.8 × 4.8^6)/6! = 0.14

P( 3 lesser than or equal to x lesser than or equal to 6) = 0.15 + 0.18 + 0.17 + 0.14 = 0.64

5 0

3 years ago