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4 years ago

5(4x-1)-2x=31 what does x equal

Mathematics

2 answers:

Elenna [48]4 years ago

6 0

Answer:

X=2

Step-by-step explanation:

5(4x-1)-2x=31

Distribute the 5

20x-5-2x=31

18x-5=31

18x=31+5

18x=36

When you divide you get 2

Also, Photomath exists, it’s great for math problems

ehidna [41]4 years ago

3 0

20x - 5 - 2x = 31

18x = 36

x = 2

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Scott's gas tank is 1/3 full. After he buys 12 gallons of gas, it is 7/9 full. How many gallons can Scott's tank hold?

Bumek [7]

Answer: We start with the variable "x". Let's call "x" Dan's full tank.

So we know that right now he has 1/3x or 1/3 of a full tank.

After adding 12 gallons, at the end, he has 7/9x, or 7/9 of a full tank

So we start with

(1/3)x + 12 = 7/9x

Let's subtract 1/3x from both sides

12 = 7/9x - 1/3x

Remember, we need to use common denominators to subtract, so 1/3 becomes 3/9

12 = 7/9x - 3/9x

Now we simplify to get

12 = 4/9x

Multiply the reciprocal of 4/9 to both sides which is 9/4

12 * 9/4 = x

Answer is 27 gallons.

6 0

3 years ago

The equation 2x2 − 12x + 1 = 0 is being rewritten in vertex form. Fill in the missing step. Given 2x2 − 12x + 1 = 0 Step 1 2(x2

Bezzdna [24]

Answer:

Part 1) $2(x-3)^{2}-17=0$ (the missing steps in the explanation)

Part 3) (8, 4); The vertex represents the maximum profit

Part 4) x = 3.58, 0.42

Part 5) x = 6, x = 44; The zeros represent the number of monthly memberships where no profit is made

Part 6) 2(x − 7)2 + 118; x = $7

Part 7) The maximum height of the puck is 4 feet. −(x − 4)^2 + 6

Part 8) (x + 3)^2 − 4

Part 9) 2(x − 1)^2 = 4

Part 10) 8(x − 4)^2 + 592

Step-by-step explanation:

Part 1) we have

$2x^{2} -12x+1=0$

Convert to vertex form

step 1

Factor the leading coefficient and complete the square

$2(x^{2} -6x)+1=0$

$2(x^{2} -6x+9)+1-18=0$

step 2

$2(x^{2} -6x+9)+1-18=0$

$2(x^{2} -6x+9)-17=0$

step 3

Rewrite as perfect squares

$2(x-3)^{2}-17=0$

Part 3) we have

$f(x)=-x^{2}+16x-60$

we know that

This is the equation of a vertical parabola open downward

The vertex is a maximum

Convert to vertex form

$f(x)+60=-x^{2}+16x$

Factor the leading coefficient

$f(x)+60=-(x^{2}-16x)$

Complete the squares

$f(x)+60-64=-(x^{2}-16x+64)$

$f(x)-4=-(x^{2}-16x+64)$

Rewrite as perfect squares

$f(x)-4=-(x-8)^{2}$

$f(x)=-(x-8)^{2}+4$

The vertex is the point (8,4)

The vertex represent the maximum profit

Part 4) Solve for x

we have

$-2(x-2)^{2}+5=0$

$-2(x-2)^{2}=-5$

$(x-2)^{2}=2.5$

square root both sides

$(x-2)=(+/-)1.58$

$x=2(+/-)1.58$

$x=2(+)1.58=3.58$

$x=2(-)1.58=0.42$

Part 5) we have

$f(x)=-x^{2}+50x-264$

we know that

The zeros or x-intercepts are the value of x when the value of the function is equal to zero

In this context the zeros represent the number of monthly memberships where no profit is made

To find the zeros equate the function to zero

$-x^{2}+50x-264=0$

$-x^{2}+50x=264$

Factor -1 of the leading coefficient

$-(x^{2}-50x)=264$

Complete the squares

$-(x^{2}-50x+625)=264-625$

$-(x^{2}-50x+625)=-361$

$(x^{2}-50x+625)=361$

Rewrite as perfect squares

$(x-25)^{2}=361$

square root both sides

$(x-25)=(+/-)19$

$x=25(+/-)19$

$x=25(+)19=44$

$x=25(-)19=6$

Part 6) we have

$-2x^{2}+28x+20$

This is a vertical parabola open downward

The vertex is a maximum

Convert the equation into vertex form

Factor the leading coefficient

$-2(x^{2}-14x)+20$

Complete the square

$-2(x^{2}-14x+49)+20+98$

$-2(x^{2}-14x+49)+118$

Rewrite as perfect square

$-2(x-7)^{2}+118$

The vertex is the point (7,118)

therefore

The video game price that produces the highest weekly profit is x=$7

Part 7) we have

$f(x)=-x^{2}+8x-10$

Convert to vertex form

$f(x)+10=-x^{2}+8x$

Factor -1 the leading coefficient

$f(x)+10=-(x^{2}-8x)$

Complete the square

$f(x)+10-16=-(x^{2}-8x+16)$

$f(x)-6=-(x^{2}-8x+16)$

Rewrite as perfect square

$f(x)-6=-(x-4)^{2}$

$f(x)=-(x-4)^{2}+6$

The vertex is the point (4,6)

therefore

The maximum height of the puck is 4 feet.

Part 8) we have

$x^{2}+6x+5$

Convert to vertex form

Group terms

$(x^{2}+6x)+5$

Complete the square

$(x^{2}+6x+9)+5-9$

$(x^{2}+6x+9)-4$

Rewrite as perfect squares

$(x+3)^{2}-4$

Part 9) we have

$2x^{2}-4x-2=0$

This is the equation of a vertical parabola open upward

The vertex is a minimum

Convert to vertex form

Factor 2 the leading coefficient

$2(x^{2}-2x)-2=0$

Complete the square

$2(x^{2}-2x+1)-2-2=0$

$2(x^{2}-2x+1)-4=0$

Rewrite as perfect squares

$2(x-1)^{2}-4=0$

$2(x-1)^{2}=4$

The vertex is the point (1,-4)

Part 10) we have

$8x^{2}-64x+720$

This is the equation of a vertical parabola open upward

The vertex is a minimum

Convert to vertex form

Factor 8 the leading coefficient

$8(x^{2}-8x)+720$

Complete the square

$8(x^{2}-8x+16)+720-128$

$8(x^{2}-8x+16)+592$

Rewrite as perfect squares

$8(x-4)^{2}+592$

the vertex is the point (4,592)

The population has a minimum at x=4 years ( that is after 4 years since 1998 )

6 0

3 years ago

For the region bounded by y=2x, the x-axis, and x=1, determine which of the following is greater: the volume of the solid ge

telo118 [61]

Answer:

The correct answer B) The volumes are equal.

Step-by-step explanation:

The area of a disk of revolution at any x about the x- axis is πy² where y=2x. If we integrate this area on the given range of values of x from x=0 to x=1 , we will get the volume of revolution about the x-axis, which here equals,

$\int\limits^1_0 {(pi)y^{2} } \, dx$

which when evaluated gives 4pi/3.

Now we have to calculate the volume of revolution about the y-axis. For that we have to first see by drawing the diagram that the area of the CD like disk centered about the y-axis for any y, as we rotate the triangular area given in the question would be pi - pi*x². if we integrate this area over the range of value of y that is from y=0 to y=2 , we will obtain the volume of revolution about the y-axis, which is given by,

$\int\limits^2_0 {pi - pix^{2} } \, dy = \int\limits^2_0 {1 - y^{2}/4 } \, dy$

If we just evaluate the integral as usual we will get 4pi/3 again(In the second step i have just replaced x with y/2 as given by the equation of the line), which is the same answer we got for the volume of revolution about the x-axis. Which means that the answer B) is correct.

7 0

3 years ago

Find the GFC of 56 and 84. A factor tree for 84 is given below. The GCF of 84 and 56 is 7142128 .

guajiro [1.7K]

Answer:

28 is the GCF

Step-by-step explanation:

What I know about GCF is that it's a greatest (G) common (C) factor (F). The GCF of 84 and 56 is 7142128; false.

56- 56, 28, 14, 8, 7, 4, 2, 1.

84- 84, 42, 28, 21, 14, 12, 7, 6, 4, 3, 2, 1.

Hope this helps. :)

8 0

3 years ago

Read 2 more answers

A long paper strip with a width of 5 cm is folded, as shown in the picture. Find the smallest possible area of the gray triangle

Stolb23 [73]

By using some logic and the formula of the triangle's area, we will find that the smallest possible area is 12.5 cm²

How to start thinking about the problem.

First of all, for the configuration of this paper strip, we can see that the base of the triangle will always be equal of the width of the paper. Thus, the smallest area will be only dependent of the height of the triangle.

Now, we need to analyze the picture to figure out how we can get the smallest height possible for that triangle.

What is the smallest height possible.

Doing this, we shall see that the smallest height possible is actually when the height equals the width itself, as it's shown in the attached image.

How to calculate the smallest area possible.

Thus, to calculate the smallest area, we just have to use the formula of the area of the triangle, which is $\frac{b\times h}{2}$ , where b is the base and h is the height.

As we previously found, for this question, the

base = height = width of the paper = 5cm

Now, we just have to calculate it with the formula

$Area = \frac{base \times height}{2} \\\\
\\
Area = \frac{5 \times 5}{2} \\
\\
Area = \frac{25}{2}\\
 \\
Area = 12.5 cm^{2}$

learn more about the area of the triangle here: brainly.com/question/15442893

3 0

2 years ago