All categories

2 years ago

Solve the system by substitution. - 2 + 3y = 20 7y = x

Mathematics

1 answer:

Savatey [412]2 years ago

3 0

Answer:

x = 22, y = 22/7

Step-by-step explanation:

solve for y using first equation:

-2 + 3y = 20

3y = 22

y = 22/7

substitute 22/7 into second equation:

7y = x

7(22/7) = x

x = 22

You might be interested in

Help ASAP PLEASE look like a

Ray Of Light [21]

The answer should be B.

7 0

3 years ago

Read 2 more answers

Gravel is being dumped from a conveyor belt at a rate of 20 ft3 /min and its coarseness is such that it forms a pile in the shap

pantera1 [17]

Answer:

The height of the pile is increasing at the rate of $\mathbf{ \dfrac{20}{56.25 \pi} \ \ \ \ \ ft/min}$

Step-by-step explanation:

Given that :

Gravel is being dumped from a conveyor belt at a rate of 20 ft³ /min

i.e $\dfrac{dV}{dt}= 20 \ ft^3/min$

we know that radius r is always twice the diameter d

i.e d = 2r

Given that :

the shape of a cone whose base diameter and height are always equal.

then d = h = 2r

h = 2r

r = h/2

The volume of a cone can be given by the formula:

$V = \dfrac{\pi r^2 h}{3}$

$V = \dfrac{\pi (h/2)^2 h}{3}$

$V = \dfrac{1}{12} \pi h^3$

$V = \dfrac{ \pi h^3}{12}$

Taking the differentiation of volume V with respect to time t; we have:

$\dfrac{dV}{dt }= (\dfrac{d}{dh}(\dfrac{\pi h^3}{12})) \times \dfrac{dh}{dt}$

$\dfrac{dV}{dt }= (\dfrac{\pi h^2}{4} ) \times \dfrac{dh}{dt}$

we know that:

$\dfrac{dV}{dt}= 20 \ ft^3/min$

So;we have:

$20= (\dfrac{\pi (15)^2}{4} ) \times \dfrac{dh}{dt}$

$20= 56.25 \pi \times \dfrac{dh}{dt}$

$\mathbf{\dfrac{dh}{dt}= \dfrac{20}{56.25 \pi} \ \ \ \ \ ft/min}$

The height of the pile is increasing at the rate of $\mathbf{ \dfrac{20}{56.25 \pi} \ \ \ \ \ ft/min}$

8 0

3 years ago

Solve the inequality and enter your solution as an inequality comparing the variable to the solution in the box below. 18 + x &g

storchak [24]

Hi there! :)

Answer:

x>24

*The answer must have a positive sign and greater than symbol sign.*

Step-by-step explanation:

First, you switch sides.

$x+18>42$

Then, you subtract by 18 from both sides of an equation.

$x+18-18>42-18$

Finally, you subtract by the numbers from left to right.

$42-18=24$

Final answer is x>24

I hope this helps you!

Have a nice day! :)

-Charlie

7 0

2 years ago

A radioactive substance decays at a rate of 3.4% per day. If it starts at 200 grams, how

Goshia [24]

Answer: 9

Step-by-step explanation:

Since the percent is decaying, you subtract 3.4 from 100, which gets you 96.6

200(0.966)^9 gets you 146.5 which is less than 150

3 0

3 years ago

I really need the answers as soon as possible. So I hope you answer this

SpyIntel [72]

Ignore bottom one please brainiest. edit: add cubed after the second bracket

8 0

2 years ago