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3 years ago

What are the solutions to the equation? 7x^3=28x

Mathematics

1 answer:

11Alexandr11 [23.1K]3 years ago

6 0

7x³ = 28x is our equation. We want its solutions.

When you have x and different powers, set the whole thing equal to zero.

7x³ = 28x

7x³ - 28x = 0

Now notice there's a common x in both terms. Let's factor it out.

x (7x² - 28) = 0

As 7 is a factor of 7 and 28, it too can be factored out.

x (7) (x² - 4) = 0

We can further factor x² - 4. We want a pair of numbers that multiply to 4 and whose sum is zero. The pairs are 1 and 4, 2 and 2. If we add 2 and -2 we get zero.

x (7) (x - 2) (x + 2) = 0

Now we use the Zero Product Property - if some product multiplies to zero, so do its pieces.

x = 0 -----> so x = 0

7 = 0 -----> no solution

x - 2 = 0 ----> so x = 2 after adding 2 to both sides

x + 2 = 0 ---> so = x - 2 after subtracting 2 to both sides

Thus the solutions are x = 0, x = 2, x = -2.

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Step-by-step explanation:

g(x) = (x+4)² - 5

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3/5 of the students in a classroom are girls if there are 10 boys in the class how many total students are there

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3 years ago

A company's stock begins the week with a price of $43.85 per share. THe price changes by +$2.70 each day for the first two days,

mixas84 [53]

Given:

Initial price of the stock=$43.85

Change for the first two days=+$2.70

Change for next two days=-$1.10

Last day=-$4.45

The objective is to find the price at the last day.

Let's take the price at final day as x.

$\begin{gathered} x=43.85+2.70+2.70-1.10-1.10-4.45 \\ x=42.6 \end{gathered}$

Hence, the price of the stock at the last day is $42.6

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1 year ago

What is the length of the diagonal?

Juliette [100K]

Answer:

The value of x is equal to 26 cm.

Step-by-step explanation:

We can use the Pythagorean Theorem to solve this problem.

$a^2+b^2=c^2$

$a=10\\b=24\\c=?$

$10^2+24^2=c^2$

$100+576=c^2$

$676=c^2$

$\sqrt{676} =\sqrt{c^2}$

$26=c$

6 0

3 years ago

Given: △ABC, AB=5sqrt2 m∠A=45°, m∠C=30° Find: BC and AC

Marysya12 [62]

BC is 10 units and AC is $5+5\sqrt{3}$ units

Step-by-step explanation:

Let us revise the sine rule

In ΔABC:

$\frac{AB}{sin(C)}=\frac{BC}{sin(A)}=\frac{AC}{sin(B)}$
AB is opposite to ∠C
BC is opposite to ∠A
AC is opposite to ∠B

Let us use this rule to solve the problem

In ΔABC:

∵ m∠A = 45°

∵ m∠C = 30°

- The sum of measures of the interior angles of a triangle is 180°

∵ m∠A + m∠B + m∠C = 180

∴ 45 + m∠B + 30 = 180

- Add the like terms

∴ m∠B + 75 = 180

- Subtract 75 from both sides

∴ m∠B = 105°

∵ $\frac{AB}{sin(C)}=\frac{BC}{sin(A)}$

∵ AB = $5\sqrt{2}$

- Substitute AB and the 3 angles in the rule above

∴ $\frac{5\sqrt{2}}{sin(30)}=\frac{BC}{sin(45)}$

- By using cross multiplication

∴ (BC) × sin(30) = $5\sqrt{2}$ × sin(45)

∵ sin(30) = 0.5 and sin(45) = $\frac{1}{\sqrt{2}}$

∴ 0.5 (BC) = 5

- Divide both sides by 0.5

∴ BC = 10 units

∵ $\frac{AB}{sin(C)}=\frac{AC}{sin(B)}$

- Substitute AB and the 3 angles in the rule above

∴ $\frac{5\sqrt{2}}{sin(30)}=\frac{AC}{sin(105)}$

- By using cross multiplication

∴ (AC) × sin(30) = $5\sqrt{2}$ × sin(105)

∵ sin(105) = $\frac{\sqrt{6}+\sqrt{2}}{4}$

∴ 0.5 (AC) = $\frac{5+5\sqrt{3}}{2}$

- Divide both sides by 0.5

∴ AC = $5+5\sqrt{3}$ units

BC is 10 units and AC is $5+5\sqrt{3}$ units

Learn more:

You can learn more about the sine rule in brainly.com/question/12985572

#LearnwithBrainly

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3 years ago