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3 years ago

Find the value of the expression 3x plus 4y when x= 4 and y= 5

Mathematics

2 answers:

Alisiya [41]3 years ago

8 0

Answer:

Step-by-step explanation:

Stella [2.4K]3 years ago

6 0

Answer:

Step-by-step explanation:

Substitute x and y for their numbers.

(3*4)+(4*5)

12+20

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You might be interested in

The radius of a cone is decreasing at a constant rate of 7 inches per second, and the volume is decreasing at a rate of 948 cubi

nadezda [96]

Answer:

Step-by-step explanation:

We have volume of cone as

$V=\frac{1}{3} \pi r^2 h$

and for a cone always r/h = constant

Given that r' = rate of change of radius = -7 inches/sec

(Negative sign because decresing)

V' =- 948 in^3/sec

Radius = 99 inches and volume = 525 inches

Height at this instant = $\frac{525}{\frac{1}{3} \pi (99)^2} \\=\frac{0.1607}{\pi}$

Let us differentiate the volume equation with respect to t using product rule

$V=\frac{1}{3} \pi r^2 h\\V' = \frac{1}{3} \pi[2rhr'+r^2 h']\\-948 = \frac{1}{3} \pi[2(99)(-7)(\frac{0.1607}{\pi})+99^2 h']\\$

$-948 = \frac{1}{3} \pi[2(99)(-7)(\frac{0.1607}{\pi})+99^2 h']\\-948 = 33(3.14)(-2.25/3.14 + 99 h')\\-9.149=-0.72+99h'\\-8.429 = 99h'\\h' = 0.08514$

Rate of change of height = 0.08514 in/sec

8 0

3 years ago

In order for Clorox to act as a disinfectant for teat dipping the solution must

LUCKY_DIMON [66]

Answer:

$V = 200\,mL$

Step-by-step explanation:

The distilled water is solute and the bleach is the solvent. The amount needed of bleach is:

$V = \frac{2}{5}\cdot (500\,mL)$

$V = 200\,mL$

5 0

3 years ago

75 POINTS Need an immediate answer please brainliest will be given! A train left a station travelling to a city at 30 mph. The t

yaroslaw [1]

The value of distance between the station and the city in terms of miles which train and car travelled at interval of 2 hours is 129.6 miles.

<h3>What is the rate of speed?</h3>

The rate of speed is the rate at which the total distance is travelled in the time taken. Rate of speed can be given as,

r=d/t

Here, (d) is the distance travelled by the object and (t) is time taken but the object to cover that distance.

The train traveled 1/3 of the distance at 30 mph and the remaining distance at 40 mph. Let <em>t</em> is the time the train has taken to travel and x is the distance it travelled. Thus,

$t=\dfrac{\dfrac{1}{3}x}{30}+\dfrac{\dfrac{2}{3}x}{40}\\t=\dfrac{x}{90}+\dfrac{x}{60}\\t=\dfrac{2x+3x}{180}\\t=\dfrac{5x}{180}\\t=\dfrac{x}{36}$

After two hour a car left the same station traveled the first 3 hours at 35 mph and the remaining distance at 51 mph. Let <em>t</em> is the time the car has taken to travel and x is the distance it travelled. Thus,

$t+2=3+\dfrac{(x-3\times35)}{51}$

As t is same, thus put the value of t in this equation,

$\dfrac{x}{36}=3-2+\dfrac{(x-3\times35)}{51}\\\dfrac{x}{36}=3-2+\dfrac{(x-3\times35)}{51}\\\dfrac{x}{36}=1+\dfrac{(x-105)}{51}\\\dfrac{x}{36}=\dfrac{(51+x-105)}{51}\\51x=36x-54\times36\\51x-36x=1944\\x=\dfrac{1944}{15}\\x=129.6$

Thus, the value of distance between the station and the city in terms of miles which train and car travelled at interval of 2 hours is 129.6 miles.

Learn more about the rate of speed here:

brainly.com/question/359790

#SPJ1

6 0

2 years ago

Need help WILL MARK BRAINLEST

zimovet [89]

root 12 + 5 root 3

2 root 3 + 5 root 3

7 root 3

7 0

3 years ago

Suppose $2000 is invested at 9% interest compounded continuously. How long will it take for the investment to grow to $10,000? U

Lady bird [3.3K]

Answer:

Step-by-step explanation:

sing the equation > A = Pe^rt

20000 = 10000e^0.1t > 10% = 0.1

2 = e^0.1t

log 2 = log e^0.1t > log to the base e

log 2 = 0.1t * 1 log e to the base e =1

0.6931 = 0.1t

t = 6.931

= 7 years

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4 0

3 years ago