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3 years ago

Work out the value of 4(2x+3y) when x=8 and y=-3

Mathematics

2 answers:

timofeeve [1]3 years ago

8 0

I think it may be 28.

Sav [38]3 years ago

3 0

Here’s the steps if you need it. And yes, the answer is 28.

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The position function of a particle in rectilinear motion is given by s(t) = 2t3 – 21t2 + 60t + 3 for t ≥ 0 with t measured in s

Norma-Jean [14]

The positions when the particle reverses direction are:

$s(t_1)=55ft\\\\s(t_2)=28ft$

The acceleraton of the paticle when reverses direction is:

$a(t_1)=-18\frac{ft}{s^{2}}\\ \\a(t_2)=a(5s)=18\frac{ft}{s^{2}}$

Why?

To solve the problem, we need to remember that if we derivate the position function, we will get the velocity function, and if we derivate the velocity function, we will get the acceleration function. So, we will need to derivate two times.

Also, when the particle reverses its direction, the velocity is equal to 0.

We are given the following function:

$s(t)=2t^{3}-21t^{2}+60t+3$

So,

- Derivating to get the velocity function, we have:

$v(t)=\frac{ds}{dt}=(2t^{3}-21t^{2}+60t+3)\\\\v(t)=3*2t^{2}-2*21t+60*1+0\\\\v(t)=6t^{2}-42t+60$

Now, making the function equal to 0, to find the times when the particle reversed its direction, we have:

$v(t)=6t^{2}-42t+60\\\\0=6t^{2}-42t+60\\\\0=t^{2}-7t+10\\(t-5)*(t-2)=0\\\\t_{1}=5s\\t_{2}=2s$

We know that the particle reversed its direction two times.

- Derivating the velocity function to find the acceleration function, we have:

$a(t)=\frac{dv}{dt}=6t^{2}-42t+60\\\\a(t)=12t-42$

Now, substituting the times to calculate the accelerations, we have:

$a(t_1)=a(2s)=12*2-42=-18\frac{ft}{s^{2}}\\ \\a(t_2)=a(5s)=12*5-42=18\frac{ft}{s^{2}}$

Now, substitutitng the times to calculate the positions, we have:

$s(t_1)=2*(2)^{3}-21*(2)^{2}+60*2+3=16-84+120+3=55ft\\\\s(t_2)=2*(5)^{3}-21*(5)^{2}+60*5+3=250-525+300+3=28ft$

Have a nice day!

3 0

3 years ago

Which function is graphed?

Lapatulllka [165]

Answer:

I think that a Cube Root Function

Step-by-step explanation:

3 0

3 years ago

A student has gotten the following grades on his tests. What is the minimum grade he must get on the last test in order to have

arsen [322]

The lowest grade that student could get is a 91 or higher

7 0

3 years ago

On a particular airline, bags checked in must weigh less than 50 pounds. Betty packed 32 pounds of clothes and five gifts that w

andreev551 [17]

Answer:

5x + 32 < 50

Step-by-step explanation:

On a particular airline, bags checked in must weigh less than 50 pounds. Betty packed 32 pounds of clothes and five gifts that weigh the same amount.

If each gift weighs w pounds, then the weight of five gifts will be 5w pounds and an additional 32 pounds of clothes will make it total (32 + 5w) pounds.

Now, this total weight has to be less than 50 pounds.

Therefore, the inequality equation that can be used to find the possible weight of each gift, w is

5x + 32 < 50 (Answer)

3 0

3 years ago

ONLY answer if you know what the answer is. If you are not sure DONT FREAKING ANSWER.

Bogdan [553]

Answer:

5 = |-5|

Step-by-step explanation:

Think of it as a number line, like in the picture below. The absolute value is how far a number is from zero (0). If 5 is 5 away from zero, then the opposite of 5 (-5) is also 5 away from zero.

Refer to the picture below for an illustration:

8 0

2 years ago

Read 2 more answers