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3 years ago

Use the substitution method to solve the system of equations. y=7x +8 y=x +20

Mathematics

1 answer:

DanielleElmas [232]3 years ago

3 0

Answer:

Step-by-step explanation:

$\left\{\begin{array}{ccc}y=7x+8&(1)\\y=x+20&(2)\end{array}\right\qquad\text{substitute (1) to (2):}\\\\7x+8=x+20\qquad\text{subtract 8 from both sides}\\7x=x+12\qquad\text{subtract x from both sides}\\6x=12\qquad\text{divide both sides by 6}\\x=2\\\\\text{put the value of x to (2):}\\\\y=2+22\\y=22$

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I would say 19 because 300 is the right way

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3 years ago

If the area of the circle is 225pi what is the diameter

Stells [14]

Answer:

30cm

Step-by-step explanation:

Area is πr²

So,

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3 years ago

Question 22 A city has a population of people. Suppose that each year the population grows by . What will the population be afte

Alexeev081 [22]

Answer:

911,690.

Step-by-step explanation:

Please consider the complete question.

A city has a population of 390,000 people. Suppose that each year the population grows by 6.75%. What will the population be after 13 years? Round your answer the nearest whole number.

We will use exponential growth formula to solve our given problem.

$y=a\cdot (1+r)^x$ , where,

y = Final value,

a = Initial value,

r = Growth rate in decimal form,

$6.75\%=\frac{6.75}{100}=0.0675$

$y=390,000\cdot (1+0.0675)^x$

$y=390,000\cdot (1.0675)^x$

To find the population after 13 years, we will substitute $x=13$ in population growth equation as:

$y=390,000\cdot (1.0675)^{13}$

$y=390,000\cdot 2.3376661492982871$

$y=911689.798226331969$

Upon rounding to nearest whole number, we will get:

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Therefore, the population of the city after 13 years would be 911,690.

8 0

3 years ago

PLEASE help me! The question is attached.

ycow [4]

Answer:

The third option is correct

Step-by-step explanation:

We can rule out the first option because systems of equations CAN have decimal answers (this certain question cannot because of the domain) Same for the second option.

The last option says that all the numbers of forks knives and spoons must be equal but the question never specified that, in fact it looks like that is impossible since the variables have different coefficients.

The only logical answer is number 3

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3 years ago

Y = -6, W = 7, j = -2<br><br> - 2y +w-4j

Reika [66]

Answer:

answer is 27

Step-by-step explanation:

-2(-6) + 7 -4(-2)

12+7+8

19+8

Hope this helped

7 0

3 years ago

Use the substitution method to solve the system of equations. y=7x +8 y=x +20​

Use the substitution method to solve the system of equations. y=7x +8 y=x +20