Which expression can be used to find the difference of the polynomials? (10m – 6) – (7m

Victoria has $2.90 in quarters, dimes and nickels. The numbers of nickels is one more than six times the number of quarters, and

maria [59]

Answer:

Step-by-step explanation:

She has 290 cents.

Nickels: 6x+1

Quarters: x

Dimes: 4x

Now that we've converted it algebraically, we can add them

6x+1 + x + 4x = 11x+1 = 290

11x = 289

x = 289/11

let me know if incorrect, i will fix

8 0

2 years ago

Solve the equation :<br>-3 • ( 2 - x ) + 4 = 2 • ( 1 - 2x) + 3<br>thanks :)

kakasveta [241]

Isolate the variable by dividing each side by factors that don't contain the variable.

x = 1

-6+3x+4=2-4x+3

-8+7x+1=0

7x=7

x=1

4 0

2 years ago

a used truck for $4,500 he made an agreement with the dealer to put $1,500 and make payments of 350 for the next 10 months that

Aneli [31]

Ist amount paid = $1500
Making $350 for 10 months = 10*350 = $3500
Total amount paid = 1500 + 3500 = 5000
So an amount of $5000 was paid to cover the cost of $4500 within the ten month period.
I = PRT
Interest, I = 5000 - 4500 = 500Time, t = 10 months = 10/12 = (5/6) year.Principal P = 4500
R = I /(PT) R = 500 / (4500*5/6)
R = (500*6) / (4500*5)
R = 0.1333..
R ≈ 13.33 % per annum.

3 0

3 years ago

Tourists covered 640 km for a 4 hour ride by car and a 7 hour ride by train. What is the speed of the train, if it is 5 km/h gre

gavmur [86]

Answer:

60 km/h

Step-by-step explanation:

Let us use the x to represent the speed of the car since it is the smaller value.

Then, the distance covered by the car is 4x since was going 4 kph.

The distance covered by the train is (x+5) times 7 or 7x+35.

We know that the total distance covered is 640 km.

Using this information, we can set up the equation 4x+7x+35=640.

By subtracting both sides by 35 and combining the x's, we get a new equation of 11x=605.

After this, we divide both sides by 11 and get x=55.

Lastly, we add 5 to 55 since the train is 5 km faster than the car and that x stood for the car.

Train=60 km/h

5 0

2 years ago

Problem 10: A tank initially contains a solution of 10 pounds of salt in 60 gallons of water. Water with 1/2 pound of salt per g

AysviL [449]

Answer:

The quantity of salt at time t is $m_{salt} = (60)\cdot (30 - 29.833\cdot e^{-\frac{t}{10} })$ , where t is measured in minutes.

Step-by-step explanation:

The law of mass conservation for control volume indicates that:

$\dot m_{in} - \dot m_{out} = \left(\frac{dm}{dt} \right)_{CV}$

Where mass flow is the product of salt concentration and water volume flow.

The model of the tank according to the statement is:

$(0.5\,\frac{pd}{gal} )\cdot \left(6\,\frac{gal}{min} \right) - c\cdot \left(6\,\frac{gal}{min} \right) = V\cdot \frac{dc}{dt}$

Where:

$c$ - The salt concentration in the tank, as well at the exit of the tank, measured in $\frac{pd}{gal}$ .

$\frac{dc}{dt}$ - Concentration rate of change in the tank, measured in $\frac{pd}{min}$ .

$V$ - Volume of the tank, measured in gallons.

The following first-order linear non-homogeneous differential equation is found:

$V \cdot \frac{dc}{dt} + 6\cdot c = 3$

$60\cdot \frac{dc}{dt} + 6\cdot c = 3$

$\frac{dc}{dt} + \frac{1}{10}\cdot c = 3$

This equation is solved as follows:

$e^{\frac{t}{10} }\cdot \left(\frac{dc}{dt} +\frac{1}{10} \cdot c \right) = 3 \cdot e^{\frac{t}{10} }$

$\frac{d}{dt}\left(e^{\frac{t}{10}}\cdot c\right) = 3\cdot e^{\frac{t}{10} }$

$e^{\frac{t}{10} }\cdot c = 3 \cdot \int {e^{\frac{t}{10} }} \, dt$

$e^{\frac{t}{10} }\cdot c = 30\cdot e^{\frac{t}{10} } + C$

$c = 30 + C\cdot e^{-\frac{t}{10} }$

The initial concentration in the tank is:

$c_{o} = \frac{10\,pd}{60\,gal}$

$c_{o} = 0.167\,\frac{pd}{gal}$

Now, the integration constant is:

$0.167 = 30 + C$

$C = -29.833$

The solution of the differential equation is:

$c(t) = 30 - 29.833\cdot e^{-\frac{t}{10} }$

Now, the quantity of salt at time t is:

$m_{salt} = V_{tank}\cdot c(t)$

$m_{salt} = (60)\cdot (30 - 29.833\cdot e^{-\frac{t}{10} })$

Where t is measured in minutes.

7 0

3 years ago

Which expression can be used to find the difference of the polynomials? (10m – 6) – (7m – 4)