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3 years ago

Explain how to find 40x80 using mental math

Mathematics

2 answers:

nadya68 [22]3 years ago

5 0

so 40 * 80 = 3,200

4 * 8 = 32

Then add the two 0's to the end

so 3,200

skelet666 [1.2K]3 years ago

4 0

Answer:

The best way to solve 40x80 using mental math is to break down the problem.One example would be to solve 4x8 then add the two zeros to your answer to get 3200.

Step-by-step explanation:

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Simplify the expression: <br> r -3 -r

Ymorist [56]

Answer:

$-3$

Step-by-step explanation:

Combine the opposite terms in r − 3 − r .

8 0

2 years ago

Sally is having a problem with her puppy leaving the yard so she decides to build a new fence. The length of the yard is 10 feet

Cerrena [4.2K]

The length of the yard is 25ft.

In order to find this we first need to set up variables for the length and the width. Since we don't know anything about the width, we'll set it as x. Then, we know the length is equal to ten more than three times the width. Since the width is x, we can write the length as 3x + 10. Now we can use the formula for the perimeter of a rectangle to solve for x.

2l + 2w = P

2(3x + 10) + 2(x) = 60

6x + 20 + 2x = 60

8x + 20 = 60

8x = 40

x = 5

Now that we have a value for x, we can plug into the length equation and find the length.

3x + 10

3(5) + 10

15 + 10

8 0

3 years ago

The table lists how poverty level income cutoffs (in dollars) for a family of four have changed over time. Use the midpoint for

frez [133]

The poverty level cutoff in 1987 to the nearest dollar was $10787.

<h3>How to find a midpoint?</h3>

The midpoint as the point that divides the line segment exactly in half having two equal segments. Therefore, the midpoint presents the same distance between the endpoints for the line segment. The midpoint formula is: $\mathrm{Midpoint\:of\:}\left(x_1,\:y_1\right),\:\left(x_2,\:y_2\right):\quad \left(\frac{x_2+x_1}{2},\:\:\frac{y_2+y_1}{2}\right)$ .

For solving this exercise, first you need plot the points in a chart. See the image.

Your question asks to approximate the poverty level cutoff in 1987 to the nearest dollar using the midpoint formula. Note that the year 1987 is between 1980 and 1990, thus you should apply the midpoint formula from data for this year (1987).

$\mathrm{Midpoint\:of\:}\left(1980,8429),\:\left(1990,13145):\quad \left(\frac{1990+1980}{2},\:\:\frac{13145+8429}{2}\right)\\\\ \\$

$\mathrm{Midpoint\:of\:}\left(1980,8429)\:=\left(\frac{1990+1987}{2},\:\frac{13145+3843}{2}\right)\\ \\ =\left(\frac{3977}{2},\:\frac{21574}{2}\right)$

$\mathrm{Midpoint\:of\:}\left(1980,8429)\:=\=(\frac{3977}{2},10787)$

The answer for your question will be the value that you calculated for the y-coordinate. Then, the poverty level cutoff in 1987 to the nearest dollar was $10787.

Read more about the midpoint segment here:

brainly.com/question/11408596

7 0

2 years ago

How do I solve this equation?

Finger [1]

Think the 4 less than but not equal to as a equal sign
step 1. isolate the variable ( variable must stand alone)
step 2. subtract 12n -12n=0
step 3. since you subtract 12n from the left you must do the same to the right.
step 4. 13n - 12n =1n
step 5. the equation should look like this -4 less than but not equal to 1n
step 6. isolate the variable n
step 6. divide 1n/1 on the right and on the left -4/1 it equals -4
so, n is -4

7 0

3 years ago

Which statement is correct?

Andreyy89

Answer:

Correct statements:

Step-by-step explanation:

A line that rises from left to right has a positive slope.

A line that falls from right to left has a negative slope.

A horizontal line has no slope. (slope of 0)

4 0

3 years ago