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asambeis [7]
4 years ago
15

How can i solve by completing the square 4r^2-28r=-49

Mathematics
1 answer:
Natalija [7]4 years ago
3 0
To complete the square, the second degree term must have a coefficient of 1.
Since the second degree term here has a coefficient of 4, we start by dividing each term on both sides by 4.

4r^2 - 28r = -49

\dfrac{4r^2}{4} - \dfrac{28}{4}r = -\dfrac{49}{4}

r^2 - 7r = -\dfrac{49}{4}

Now we can complete the square.
First, we need to find what number completes the square.
We take the coefficient of the first degree term, -7 in this case.
Divide it by 2 and square it. -7 divided by 2 is the fraction -7/2.
Now we square -7/2 to get 49/4.
We add 49/4 to both sides.

r^2 - 7r + \dfrac{49}{4} = -\dfrac{49}{4} + \dfrac{49}{4}

(r - \dfrac{7}{2})^2 = 0

r - \dfrac{7}{2} = 0

r = \dfrac{7}{2}
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The sum of two numbers is 70 and their difference is 30. Find the two numbers
ikadub [295]

Answer:

Our two numbers are 50 and 20

Step-by-step explanation:

Sum means add together

Difference means subtract each other

x + y = 70

x - y = 30

subtract from each other

2x = 100

divide both sides by 2

x = 50

our first number is 50

50 + y = 70

subtract both sides by 50

y = 20

Our two numbers are 50 and 20

8 0
3 years ago
Can u help me plz thanks
Mrrafil [7]
1. x = -4 ; f(x) = -(-4) = 4
2. x = -3 ; f(x) = 2(-3) + 1 = -5
3. x = 0 ; f(x) = 2(0) + 1 = 1
4. x = 2 ; f(x) = 2 + 3 = 5
5. x = 5 ; f(x) = 5 + 3 = 8
4 0
4 years ago
Which of the following has a constant of proportionality of 2? A) y = 2x B) y = x + 2 C) 2y = x D) y + 2 = 2x
Setler [38]

The correct answer is A.


You have direct variation if x and y are modeled by the equation


y = mx


In this case, m is the constant of proportionality. So, if the constant has to be 2, the equation becomes


y = 2x


A side note: Actually, option C has a constant of proportionality of two as well, except the roles of x and y are interchanged. I chose option A because usually you want the y = mx form, but the names of the variables are obviously meaningless.

5 0
3 years ago
Read 2 more answers
Potato cause 0.32 per pound how much does 0.75 pounds of sweet potatoes cost
Semmy [17]
Answer: .24


You get this by multiplying .75 by .32 or by dividing .32 by four and multiplying by 3
5 0
3 years ago
The equation c = 35h + 60 describes a plumber's charges, c, for a job that takes h hours. Which statement is correct?
VikaD [51]

The complete question is

"The equation c = 35h + 60 describes a plumber's charges, c, for a job that takes h hours. Which statement is correct?

a. The domain of this function represents the total cost for a job

b. H is a function of C

c. The painter charges a $35 service fee in addition to an hourly rate

d. The painters hourly rate is $35.00"

The equation c = 35h + 60 describes a plumber's charges, c, for a job that takes h hours. So, the correct option is D. The painters hourly rate is $35.00

<h3>What is a function?</h3>

Function is a type of relation, or rule, that maps one input to specific single output.

The equation c = 35h + 60 describes a plumber's charges, c, for a job that takes h hours.

The fixed fee, or service fee, is $60.

$35 is the hourly fee since in the function, it is 35 that is multiplied by the number of hours.

So, the correct option is D. The painters hourly rate is $35.00

Learn more about function here:

brainly.com/question/2253924

#SPJ1

4 0
2 years ago
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