Difference of squares 9x^2-4

vaieri [72.5K]

You may need to sit down with your parents or with your teacher and
go over how to add and subtract fractions.

1). "Perimeter" means the distance all the way around the square.
With a square, all 4 sides are the same length. With this square,
every side is 1-1/4 inches long.

Perimeter = length of all 4 sides= (1-1/4) + (1-1/4) + (1-1/4) + (1-1/4) =

 (1 + 1 + 1 + 1) + (1/4 + 1/4 + 1/4 + 1/4) =

 4 + 4/4 = 5 inches .

2). (2-3/8) + (1-7/8) = (2 + 1) + (3/8 + 7/8) =

 (3) + (10/8) =

 3 + 1-1/4 = 4-1/4 .

3). The difference is (1-1/6) minus (5/6) .

Before you start to do the subtraction, write the (1-1/6) as (7/6) .

Then the subtraction is (7/6) - (5/6) = 2/6 = 1/3 .

4). This one is almost the same kind of problem as #3.
It's another subtraction.

If you need (2-1/4) all together, and you already have (1-3/8),
then the amount you still have to find, or borrow, or buy, is the
difference between those two numbers.

 (2-1/4) minus (1-3/8) .

The trick is to write the (2-1/4) in some form that you'll be able to
subtract (1-3/8) from it. When I learned how to do that, it was called
'borrowing', but I think now it's called 'regrouping'.

We need to work on (2-1/4):

-- take 1 from the 2, and change it into fourths.

 2-1/4 = 1 and 4/4 and 1/4 = 1 and 5/4

-- Now, take those 5/4, and turn them into eighths.
 Each fourth makes 2 eighths. So 5/4 = 10/8.

Now, the (2-1/4) has turned into 1-10/8 .
We did NOT change the value. It's still the same amount
as 2-1/4 , but it's just written in a different way.
And now the subtraction is easy:

 (2-1/4) minus (1-3/8) =

 (1-10/8) minus (1-3/8) = (zero and 7/8).

You need 7/8 inch more string than you already have.

5 0

3 years ago

Is 7.64 rational or irrational

Svet_ta [14]

i think its irrational

Step-by-step explanation:

4 0

3 years ago

In her first five basketball games, Tara scored 10, 11, 15, 16, and 18 points. What is the mean absolute deviation for this set

Daniel [21]

Hello there, and thank you for posting your question here on brainly.

To find mean absolute deviation, (MAD) you have to add all the numbers together, and then divide by how much numbers are in the set.

So we have to do 10 + 11 + 15 + 16 + 18, and then divide by 5.

10 + 11 + 15 + 16 + 18 ===> 70

Now, divide by 5.

70 / 5 ===> 14

The mean absolute deviation is 14.

Hope this helped! ☺♥

3 0

3 years ago

Jeremy analyses one of his parachute jumps. He draws a graph showing his velocity up to the opening of his parachute. a) Estimat

jeyben [28]

Answer:

Jeremy's acceleration is about $1\,\frac{m}{s^2}$ at t =10 s

His average speed is about 44.5 m/s in this section of his jump approximating with points on the curve (under-estimate)

His average speed is about 46 m/s if using the tangent line (over estimate)

Step-by-step explanation:

Jeremy's acceleration can be estimated by the curve's derivative at that point. That is the slope of the tangent line to the velocity curve at x = 10 sec. Please see attached image where the tangent line is drawn in orange, and the points to use to calculate its slope are drawn in green.

These points are : (6, 42) and (14,50) which using the slope formula give:

$slope=\frac{y_2-y_1}{x_2-x_1}= \frac{50-42}{14-6}=\frac{8}{8} \frac{m}{s^2} = 1\,\frac{m}{s^2}$

So his acceleration at that point is about $1\,\frac{m}{s^2}$

Now, using about the same interval of x-values (from 6 to 14), the corresponding speeds are approximately: 40 (for time 6 seconds) and 49 (for time 14 seconds (look for the red dots on the attached image). Since the average velocity is given by the integral of the function between those points divided by the length of the interval where it is calculated:

$v_{average}=\frac{area}{interval\,\,length}$

and we don't have the actual velocity function to estimate the integral, we can approximate this area by that of a trapezoid that connects the red dots with the bottom of the horizontal axis (see red trapezoid in the image). Clearly from the image, this approximation would give us an under-estimate of the actual average speed.

The area of this trapezoid is: approximately:

$Trapezoid\,\, area=(49+40)\,8/2=356$

Then the average velocity estimated from it is:

$v_{average}=\frac{356}{8} \frac{m}{s} =44.5\,\frac{m}{s}$

If the area is approximated instead with the trapezoid form by the green points we used to calculate the acceleration (this would give us an over-estimate):

$Trapezoid\,\, area=(50+42)\,8/2=368$