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3 years ago

11. Use the fact that 19 X 33 = 627 to solve the problems and justify your reasoning

Mathematics

1 answer:

topjm [15]3 years ago

8 0

<h2>19 X 33 = 627, justified.</h2>

Step-by-step explanation:

We have,

19 × 33 = 627

Use the fact and justify.

L.H.S. = 19 × 33

= (20 - 1) (20 + 13)

Using the identity,

(x - a)(x + b) = $x^{2}$ - (a - b)x - ab

Here, x = 20, a = 1 and b = 13

= $20^{2}$ - (1 - 13)20 - 1(13)

= 400 - (- 12)20 - 13

= 400 + 240 - 13

= 640 - 13

= 627

= R.H.S., justified.

Thus, 19 X 33 = 627, justified.

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Three vertices of parallelogram WXYZ are X(–2,–3), Y(0, 5), and Z(7, 7). Find the coordinates of vertex W

Serhud [2]

The coordinates of the vertex W are (5 , -1)

Step-by-step explanation:

In the parallelogram, the diagonal bisect each other

To find a missing vertex in a parallelogram do that:

Find the mid-point of a diagonal whose endpoints are given
Use this mid-point to find the missing vertex
The mid point rule is $(\frac{x_{1}+x_{2}}{2},\frac{y_{1}+y_{2}}{2})$

∵ WXYZ is a parallelogram

∴ Its diagonals are WY and XZ

∵ The diagonal bisect each other

- That mean they have the same mid-point

∴ They intersect each other at their mid-point

∵ x = (-2 , -3) and z = (7 , 7)

∴ $x_{1}$ = -2 and $x_{2}$ = 7

∴ $y_{1}$ = -3 and $y_{2}$ = 7

- Substitute them in the rule of the mid point to find the

mid-point of XZ

∴ $M_{XZ}=(\frac{-2+7}{2},\frac{-3+7}{2})=(2.5 , 2)$

∴ The mid-point of diagonals WY and XZ is (2.5 , 2)

Let us use it to find the coordinates of vertex W

∵ W = (x , y) and Y = (0 , 5)

∴ $x_{1}$ = x and $x_{2}$ = 0

∴ $y_{1}$ = y and $y_{2}$ = 5

- Equate 2.5 by the rule of the x-coordinate of the mid-point

∵ $2.5=\frac{x+0}{2}$

- Multiply both sides by 2

∴ 5 = x + 0

∴ 5 = x

∴ The x-coordinate of point W is 5

- Equate 2 by the rule of the y-coordinate of the mid-point

∵ $2=\frac{y+5}{2}$

- Multiply both sides by 2

∴ 4 = y + 5

- Subtract 5 from both sides

∴ -1 = y

∴ The y-coordinate of point W is -1

The coordinates of the vertex W are (5 , -1)

Learn more:

You can learn more about the mid-point in brainly.com/question/10480770

#LearnwithBrainly

4 0

3 years ago

At 7:00 A.M., Alicia pours a cup of tea whose temperature is 200°F. The tea starts to cool to room temperature (72°F). At 7:02 A

NeTakaya

Answer:

Part A

The most correct option is;

b. y = 128(0.989)x + 72

Part B

Ella can drink the tea after 7:22

Step-by-step explanation:

Here we have the temperature variation with time given in an exponential equation as follows;

Let the temperature at time x (in minutes) = y

Therefore, y = a × mˣ + b

Where:

b = Shift of the curve or the limit value of the decreasing exponential function as x → ∞

When y = 200, x = 0

Therefore. 200 = a × m⁰ + c = a + c

We note that c is the shift of the graph, the value upon which temperature increases = final temperature = 72°F

Hence a = 200 - 72 = 128°F

When y = 197, x = 2 minutes

Therefore, 197 = 128·m² + 72 =

m² = (197 - 72)/128 = 125/128

m = √(125/128) = 0.98821

Hence the exponential equation of cooling is presented in the following equation;

y = 128 × (0.98821)ˣ + 72

Therefore, the most correct option is b. y = 128(0.989)x + 72

Part B

When the temperature is 172°F we have;

172 = 128 × (0.989)ˣ + 72

∴ (0.989)ˣ = (172 - 72)/128 = 100/128 = 25/32

log(0.989)ˣ = log(25/32)

x·log(0.989) = log(25/32)

x = log(25/32)/log(0.989) = 22.32 minutes

Hence Ella can drink the tea after 7:22.

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3 years ago

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Found this when I was doing my own work, hope this helps.

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3 years ago

Dylan invested $20,000 in an account paying an interest rate of 5.3% compounded continuously. Assuming no deposits or withdrawal

almond37 [142]

Answer:

$24,240

Step-by-step explanation:

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