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2 years ago

Solve x2 + 6x = 7 by completing the square. Which is the solution set of the equation?

Mathematics

2 answers:

Doss [256]2 years ago

8 0

Answer:

x = 1; x = -7

Step-by-step explanation:

Given

x^2 + 6x = 7

we want to complete the square. If we have (x + a)^2 and expand it we get: x^2 + 2ax + a^2. The second term in the equation suggest that 2ax = 6x or a = 3. Then, adding 3^2 at both sides of the equation of the problem:

x^2 + 6x + 3^2 = 7 + 3^2

(x + 3)^2 = 16

x + 3 = sqrt(16)

That gives us two options

x + 3 = 4

x = 1

x + 3 = -4

x = -7

Ber [7]2 years ago

7 0

So first you have to find the perfect square that matches up with x^2 + 6x

so half of 6, and square it. your perfect square is 9

x^2 + 6x + 9 = 7 + 9

then, condense the left side of the equation into a squared binomial:

(x + 3)^2 = 16

take the square root of both sides:

x + 3 = ± √16

therefore:

x + 3 = ± 4

x = - 3 ± 4

so your solution set is:

x = 1, -7

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What is the value of x when y=10 in the equation y=4x-2

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Substitute y for 10 in the equation and solve using these steps:
10=4x+2
1) Minus 2 from both sides
8=4x
2) Divide both sides by 4 (the coefficient of x)
2=x
The value of x is 2 and we can check this by substituting it back into the original equation, 10 = (4×2)+2.

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2 years ago

Logan made a profit of $210.00 as a mobile groomer. He charged $75.00 per appointment and received $35.00 in tips, but also had

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2 years ago

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While Sam was at work, his house lost electrical power. By the time the electrical power came back on, the temperature inside th

Lunna [17]

A) 30 minutes after the air conditioner started to cool the house, the temperature inside the house has dropped to 76°F

B) $f(x)=-0.4x+88$

Step-by-step explanation:

In this problem, f(x) represents temperature, in degrees Fahrenheit, of Sam’s house x minutes after the air conditioner started to cool the house.

So we have:

x = minutes after the air conditioner started to cool the house

f(x) = temperature

Here we want to find what is the meaning of

$f(30)=76$

Which implies that:

$x=30$ , which means that 30 minutes have passed after the conditioner has started to cool the house

$f(x)=76$ , which means that the temperature of the room at that time is 76°F

So, the interpretation of f(30) =76 is that:

"30 minutes after the air conditioner started to cool the house, the temperature inside the house has dropped to 76°F"

Here we want to write explicitely a function that tells us how the temperature inside the house varies as a function of x, the number of minutes passed after the air conditioner has turned on.

We know the following information:

- At time x = 0, the temperature inside the house is 88°F

- At time x = 30 min, the temperature inside the hosue is 76°F

We can assume that the temperature inside the house changes linearly with time; so, we can describe the temperature function with the equation of a line:

$f(x)=mx+q$

where

$q$ is the value of the temperature at x = 0, so q = 88

m is the rate of change of the temperature

The rate of change can be found by calculating the rate of change of the temperature with respect to the change in time; so we find:

$m=\frac{76-88}{30-0}=-0.4$

which means that the temperature decreases by 0.4°F every minute. So, the function can be written as

$f(x)=-0.4x+88$

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2 years ago

The graph shows the amount of water that remains in a barrel after it begins to leak. The variable x represents the number of da

lukranit [14]

Answer:

-2 is your answer hope this helps!

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2 years ago

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Tennessee has a population of about 6,495,978. Its territory can be modeled as a trapezoid, as shown in the figure. Each unit on

kotegsom [21]

Answer:

The population density is 150 persons per square mile

Step-by-step explanation:

Firstly, we need to calculate the area of the trapezoid.

Mathematically, the area of a trapezoid is

(a+b)/2 * h

from the grid, we can obtain the lengths

on the x-axis , each line is 40(200/5 thin lines)

on the y-axis, each thin line also is 40(200/5 thin lines)

thus a = (8 * 40) = 320

b = (10* 40) = 400

h = (3 * 40) = 120

Inserting this into the area equation, we have the area of the trapezoid as (320 + 400)/2 * 120 = 43,200 units

since each unit = 1 mile, the area of Tennessee = 43,200 units

The population density is thus ; 6,495,978/43,200= which is approximately 150 persons per square mile

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2 years ago