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4 years ago

Will give brainliest for right answer!

Mathematics

1 answer:

Annette [7]4 years ago

8 0

This is a system of equations. We solve it by setting it up so that when we add the two equations together, one of the variables will cancel out. We can do this by multiplying the bottom equation by 3. This will make our system of equations equal:

3a + b + 225
-3a + 3b = 75

Now we add these two equations together, because the a terms will cancel out.

4b = 300.

We can find what b is by dividing both sides by 4.

b = 75

Next, we plug in b in one of the equations and solve for a. You can use either equation, but I will use the second.

75 - a = 25

Subtract 25 from both sides and add a to both sides:

a = 50

So, the first option is correct. A = 50 and b = 75.

You might be interested in

A cube is 6 feet on each side. What is its volume?

zlopas [31]

36ft

Explanation: 6x6=36

3 0

3 years ago

Read 2 more answers

5. Mrs.Weed's puppy weighed o.236 kg when it was born. At the next check-up it weighed 0.37 kg. How much weight had it gained?

musickatia [10]

Answer:

5.) 0.134 kg.

6.) 6.15 km.

7.) 5.9 kg.

Step-by-step explanation:

5.) 0.37 - 0.236 = 0.134

6.) 9.71 - 3.56 = 6.15

7.) 1.7 + 4.2 = 5.9

5 0

3 years ago

Scientists have discovered a vaccine for a debilitating disease. This year there were 570,000 reported new cases of the disease

Ket [755]

Answer: There are approximately 853827 new cases in 6 years.

Step-by-step explanation:

Since we have given that

Initial population = 570000

Rate at which population decreases is given by

$\frac{2}{3}$

Now,

First year =570000

Second year is given by

$570000\times (\frac{1}{3})$

Third year is given by

$570000(\frac{1}{3})^2$

so, there is common ratio ,

it becomes geometric progression, as there is exponential decline.

so,

$570000,570000\times \frac{1}{3},570000\times( \frac{1}{3})^2,......,570000\times (\frac{1}{3})^6$

a=570000

common ratio is given by

$r=\frac{a_2}{a_1}=\frac{1}{3}$

number of terms = 6

Sum of terms will be given by

$S_n=\frac{a(1-r^n)}{(1-r)}$

We'll put this value in this formula,

$S_6=\frac{570000(1-(\frac{1}{3})^6}{(1-\frac{1}{3})}\\\\=853827.16$

So, there are approximately 853827 new cases in 6 years.

6 0

3 years ago

The sales tax on a surfboard is $12. What is the percent of sales tax?

Rudik [331]

X= sales tax %

Step 1:
$240 * sales tax %= $12
240 * x= 12
240x=12
Divide both sides by 240
x= 0.05 (decimal of the %)

Convert to %:
Multiply decimal by 100 (or move decimal to the right two decimal places
=0.05 x 100
=5 %

The sales tax is 5%.

Hope this helps! :)

8 0

3 years ago

Evaluate the integral using integration by parts with the indicated choices of u and dv. (Use C for the constant of integration.

trasher [3.6K]

Answer:

$\frac{xe^{7x}}{7} + \frac{e^{7x}}{49}$

Step-by-step explanation:

Given the integral equation

$\int\limits{xe^{7x}} \, dx \\$

According to integration by part;

$\int\limits {u} \, dv = uv + \int\limits {v} \, du$

u = x, dv = e^7x

du/dx = 1

du = dx

$v = \int\limits {e^{7x}} \, dx \\v = e^7x/7$

Substitute the given values into the formula;

$\int\limits {xe^{7x}} \, dx = x(e^{7x}/7) + \int\limits ({e^{7x}/7}) \, dx\\\int\limits {xe^{7x}} \, dx = \frac{xe^{7x}}{7} + \frac{e^{7x}}{7*7} \\\int\limits {xe^{7x}} \, dx = \frac{xe^{7x}}{7} + \frac{e^{7x}}{49}$

3 0

3 years ago