If y=5x-7, determine the value of y when x=-3

A carpenter purchased 50 ft of redwood and 80 ft of pine for a total cost of $285. A second purchase, at the same prices, includ

Marizza181 [45]

Hey there!!

Let us take the price of the redwood as ' x ' and pine as ' y '

Then , we take it into an equation. We get,

50x + 80y = 285 -------------- ( 1 )

80x + 50y = 339 -------------- ( 2 )

Now, multiply the first equation with 8 and the second equation with 5

400x + 640y = 2280

400x + 250y = 1695

Now subtract the second equation from the first

390y = 585

y = 585 / 390

y = $1.5

Now substitute this into any equation

50x + ( 80 ) ( 1.5 ) = 285

50x + 120 = 285

50x = 165

x = 165 / 50

x = $3.3

Redwood = $3.3

Pine = $1.5

Hope helps!

6 0

3 years ago

A certain city's population is 120,000 and decreases 1.4% per year for 15 years.

mart [117]

Answer:

Decay Problem.

Decay rate, r = 0.014
Initial Amount =120,000

$P(t)=120000(0.986)^t$
P(10)=104,220

Step-by-step explanation:

The exponential function for growth/decay is given as:

$P(t)=P_0(1 \pm r)^t, where:\\P_0$ is the Initial Population\\r is the growth/decay rate\\t is time$

In this problem:

The city's initial population is 120,000 and it decreases by 1.4% per year.

Since the population decreases, it is a Decay Problem.

Decay rate, r=1.4% =0.014
Initial Amount =120,000

Therefore, the function is:

$P(t)=120000(1 - 0.014)^t\\P(t)=120000(0.986)^t$

When t=10 years

$P(10)=120000(0.986)^10\\=104219.8\\\approx 104220 $ (to the nearest whole number)$

8 0

3 years ago

Kevin has just purchased a small rectangular fish tank that holds 904.5 milliliters of water. The tank has a length of 15 cm and

Nitella [24]

Answer:

A stone is thrown straight up from the edge of a roof, 750 feet above the ground at a speed of 14 feet per second. A) Remembering that the acceleration due to gravity is -32 feet per second squared, how high is the stone 2 seconds later? B) At what time does the stone hit the ground? C) What is the velocity of the stone when it hits the ground?

Step-by-step explanation:

A stone is thrown straight up from the edge of a roof, 750 feet above the ground at a speed of 14 feet per second. A) Remembering that the acceleration due to gravity is -32 feet per second squared, how high is the stone 2 seconds later? B) At what time does the stone hit the ground? C) What is the velocity of the stone when it hits the ground?

5 0

3 years ago

Write in ordinary form : 6 x 10^-4

GuDViN [60]

6x10^-4
move 4 places to the left
The answer is 0.0006,

5 0

4 years ago

Which model represents this word problem?

Monica [59]

Answer:

9

Step-by-step explanation:

if she has 14 and then spends 5 she will have 9. 4-5=9

5 0

3 years ago