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3 years ago

Given 2x² = -8, x isa. -2b. 2c. 2i or -2id. 4i or -4i

Mathematics

1 answer:

marishachu [46]3 years ago

5 0

Your answer is (a) because 4 times 2 is 8 but since it's negative 2 it's negative 8

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Robert makes 50 litres of green paint by mixing litres of yellow paint and litres of blue paint in the ratio 2:3.

podryga [215]

Answer:

Explanation:

1. Cost of each liter of yellow paint:

Yellow paint is sold in 5 litre tins and ach tin costs £26, thus the cost of one liter is £26 / 5 liters = £5.2 per liter.

2. Cost of each liter of blue paint:

Blue paint is sold in 10 litre tins and each tin costs £48, thus the cost of one liter of blue paint is £48 / 10 liters = £4.8 per liter

3. Cost of each liter of green paint.

Green paint is made by mixing yellow paint and blue paint in the ratio 2:3

Thus, 5 liters of green paint will cost:

2 liters yellow paint: 2 liter × £5.2 / liter = £10.4

3 liters blue paint: 3 liter × £4.8 / liter = £14.4

========== ========

5 liters green paint: 5 liter £24.8

Cost of one liter of gree paint: £24.8 / 5 liter = £4.96 / liter

4. Profit

Price of each liter of green paint: £66.96 / 10 liters = £6.696 / liter = £6.70 / liter

Profit per liter = price per liter - cost per liter = £6.70/liter - £4.96 / liter = £1.74 / liter

Percentage profit = profit per liter / cost per liter × 100

Percentage profit = (£1.74 / liter) / (£4.96/liter) × 100 = 35.08% = 35%

4 0

3 years ago

Which statements about residuals are true for the least-squares regression line? I. A random scattering of residuals indicates t

Daniel [21]

Answer:

II. The sum of the residuals is always 0.

Step-by-step explanation:

A least squares regression line is a standard technique in regression analysis used to make the vertical distance obtained from the data points running to the regression line to become very minimal or as small as possible.

For any least-squares regression line, the sum of the residuals is always zero.

Basically, residuals are used to measure or determine whether or not the line of regression is a good fit or match for the data by subtracting the difference between them i.e the predicted y value and the actual y value, for the x value respectively.

Hence, the statement about residuals which is true for the least-squares regression line is that the sum of the residuals is always zero (0).

7 0

3 years ago

What kind of number is 0.87 rational or irrational

grigory [225]

Answer: it is rational

Step-by-step explanation:

7 0

2 years ago

85.87 J or heat energy is added to a 34.8 g mass of substance the temperature rises from 21.76°C

Andru [333]

Answer:

The required specific heat is 196.94 joule per kg per °C

Step-by-step explanation:

Given as :

The heat generated = Q = 85.87 J

Mass of substance (m)= 34.8 gram = 0.0348 kg

Change in temperature = T2 - T1 = 34.29°C - 21.76°C = 12.53°C

Let the specific heat = S

Now we know that

Heat = Mass × specific heat × change in temperature

Or, Q = msΔt

Or, 85.87 = (0.0348 kg ) × S × 12.53°C

Or , 85.87 = 0.4360 × S

Or, S = $\frac{85.87}{0.4360}$

∴ S = 196.94 joule per kg per °C

Hence the required specific heat is 196.94 joule per kg per °C Answer

7 0

2 years ago

PLEASE HELP! *multiple choice* List the sides in order from shortest to longest.

Amiraneli [1.4K]

Answer:

I think it's a

I'm not that sure tho

4 0

2 years ago