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3 years ago

Solve for x -x + 1 = x + 21

Mathematics

1 answer:

KatRina [158]3 years ago

5 0

Answer:

x=-10

Step-by-step explanation:

first put "x" on one side and the constants on the other

the equation becomes 2x=-20 or -2x=20

both cases divide by 2 and the answer becomes x=-10

or if you end up with -x=10 just multiply by -1 and it ends up the same

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assume these situations are proportional. write and solve by usinmg a proportion. Everardo paid $1.12 for a dozen eggs at his lo

Bingel [31]

12 eggs for $1.12
3 eggs for $?
As you can see, to get from 12 eggs to 3 eggs, you divide by 4, so do the same with $1.12 to get $0.28
The cost of 3 eggs is $0.28

8 0

4 years ago

Solve for B and C please :)

lora16 [44]

Part A

h(d) = (-1/5)d^2 + 2d is the same as h(d) = -0.2d^2 + 2d because -1/5 = -0.2

I'll use x in place of d, and y in place of h(d) to get this equivalent equation: y = -0.2x^2 + 2x

Let's find the vertex of y = -0.2x^2 + 2x

Note how y = -0.2x^2 + 2x is in the form y = ax^2+bx+c with

a = -0.2

b = 2

c = 0

So the x coordinate of the vertex is

h = -b/(2a)

h = -2/(2(-0.2))

h = 5

Plug this value into the h(d) function to compute the corresponding y coordinate

h(d) = -0.2d^2 + 2d

h(5) = -0.2(5)^2 + 2(5)

h(5) = 5

Coincidentally, the x and y coordinates of the vertex are both the same. This wont be the case in general.

-----------------

Answers:

The vertex is located at (5,5)

The interpretation is that the highest the dolphin can get is 5 feet off the surface of the water and this occurs 5 horizontal feet away from the starting point. Imagine a parabola that opens downward to have a highest point at the vertex mentioned.

====================================

Part B

From part A above, we found x = 5 to be the x coordinate of the vertex. Simply double this value to get 10 as the answer. The reason why this works is because x = 0 is the starting x intercept, or the starting point which the dolphin jumps from. Also, its because of the hint given how the vertex is between each x intercept.

If the dolphin started from any other point on the x axis, then this trick of "double the result from part A" wouldn't apply.

Part C below shows that x = 0 and x = 10 are the two x intercepts. This helps confirm the proper range.

-----------------

Answer: 10 feet

====================================

Part C

h(d) = y = height of dolphin

we want to find the two x values that make y = 0, which help us figure out when the dolphin jumps out of the water and when it lands back in the water

--------

Plug y = 0 into the equation y = -0.2x^2 + 2x and solve for x

y = -0.2x^2 + 2x

-0.2x^2 + 2x = y

-0.2x^2 + 2x = 0

x(-0.2x + 2) = 0 .... factor out x

x = 0 or -0.2x + 2 = 0 .... zero product property

x = 0 or -0.2x = -2

x = 0 or x = -2/(-0.2)

x = 0 or x = 10

-----------------

Answer:

The two x intercepts are x = 0 and x = 10

This means the parabola crosses the x axis at the locations (0,0) and (10,0).

3 0

3 years ago

To calculate the area of a circle, you may use a formula. True False

Whitepunk [10]

Answer:

True

Step-by-step explanation:

The formula for an area of a circle is a = pi times radius squared

5 0

3 years ago

Read 2 more answers

⦁ Kim's age is twice that of her sister. When you add Kim's age to her sister's age, you get 24. How old is each sister?

Vitek1552 [10]

Answer:

Kim is 16 years old and her sister is 8 years old.

Step-by-step explanation:

We can use equations to represent this scenario.

Let Kim's age be 'k' and her sister's age be 's'.

Thus, k=2s (since Kim's age is double of her sister)

and k+s=24 (their ages add to 24 (from question)

Substituting the first equation:

2s+s=24

3s=24

s=8

Therefore, Kim's sister is 8 years old.

Now substitute this value into the second equation:

k+8=24

k=16

Therefore, Kim is 16 years old.

6 0

3 years ago

Find the roots of the equation f(x) = x3 - 0.2589x2 + 0.02262x -0.001122 = 0

devlian [24]

Answer:

The root of the equation $x^3-0.2589x^{2}+0.02262x-0.001122=0$ is x ≈ 0.162035

Step-by-step explanation:

To find the roots of the equation $x^3-0.2589x^{2}+0.02262x-0.001122=0$ you can use the Newton-Raphson method.

It is a way to find a good approximation for the root of a real-valued function f(x) = 0. The method starts with a function f(x) defined over the real numbers, the function derivative f', and an initial guess $x_{0}$ for a root of the function. It uses the idea that a continuous and differentiable function can be approximated by a straight line tangent to it.

This is the expression that we need to use

$x_{n+1}=x_{n} -\frac{f(x_{n})}{f(x_{n})'}$

For the information given:

$f(x) = x^3-0.2589x^{2}+0.02262x-0.001122=0\\f(x)'=3x^2-0.5178x+0.02262$

For the initial value $x_{0}$ you can choose $x_{0}=0$ although you can choose any value that you want.

So for approximation $x_{1}$

$x_{1}=x_{0}-\frac{f(x_{0})}{f(x_{0})'} \\x_{1}=0-\frac{0^3-0.2589\cdot0^2+0.02262\cdot 0-0.001122}{3\cdot 0^2-0.5178\cdot 0+0.02262} \\x_{1}=0.0496021$

Next, with $x_{1}=0.0496021$ you put it into the equation

$f(0.0496021)=(0.0496021)^3-0.2589\cdot (0.0496021)^2+0.02262\cdot 0.0496021-0.001122 = -0.0005150$ , you can see that this value is close to 0 but we need to refine our solution.

For approximation $x_{2}$

$x_{2}=x_{1}-\frac{f(x_{1})}{f(x_{1})'} \\x_{1}=0-\frac{0.0496021^3-0.2589\cdot 0.0496021^2+0.02262\cdot 0.0496021-0.001122}{3\cdot 0.0496021^2-0.5178\cdot 0.0496021+0.02262} \\x_{1}=0.168883$

Again we put $x_{2}=0.168883$ into the equation

$f(0.168883)=(0.168883)^3-0.2589\cdot (0.168883)^2+0.02262\cdot 0.168883-0.001122=0.0001307$ this value is close to 0 but again we need to refine our solution.

We can summarize this process in the following table.

The approximation $x_{5}$ gives you the root of the equation.

When you plot the equation you find that only have one real root and is approximate to the value found.

5 0

3 years ago