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2 years ago

Solve this system of equations using the Substitution method. 3x + y = -2 y = 2x + 3

Mathematics

1 answer:

alukav5142 [94]2 years ago

6 0

Answer:

Step-by-step explanation:

we see that y = -3x-3

substitute that into the other equation to get

-3x-3 = 2x+7

-5x = 10

x = -2

so, y = -3(-2)-3 = 3

check to make sure (-2,3) solves both equations.

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If mollie can travel 250 miles in 90 minutes how far can she travel in 6 hours?

lozanna [386]

She can travel 3000 miles

7 0

3 years ago

Solve for x: 6x + 1 over 4 (4x + 8) > 12

sukhopar [10]

Answer:

A. $x>\frac{10}{7}$ .

Step-by-step explanation:

We have been given an inequality $6x+\frac{1}{4}(4x+8)>12$ . We are asked to solve the given inequality for x.

Using distributive property, we will get:

$6x+\frac{1}{4}*4x+\frac{1}{4}*8>12$

$6x+x+2>12$

$7x+2>12$

Subtract 2 from both sides:

$7x+2-2>12-2$

$7x>10$

Divide both sides by 7:

$\frac{7x}{7}>\frac{10}{7}$

$x>\frac{10}{7}$

Therefore, option A is the correct choice.

3 0

2 years ago

Sean's house is currently worth $188,900. According to a realtor, house prices in Sean's neighborhood will increase by 4.8% ever

mrs_skeptik [129]

Answer

Given

Sean's house is currently worth $188,900.

According to a realtor, house prices in Sean's neighborhood will increase by 4.8% every year.

To prove

Formula

$Compound\quaterly\ interest = Principle (1 + \frac{r}{4})^{4t}$

Where r is the rate in the decimal form.

As given

$Take\ Principle\ = P_{0}$

$Rate = \frac{4.8}{100}$

= 0.048

Put in the formula

$Compound\quaterly\ interest = P_{0}(1 + \frac{0.048}{4})^{4t}$

$Compound\quaterly\ interest = P_{0} (1 + \frac{0.048}{4})^{4t}$

$Compound\quaterly\ interest = P_{0} (1 + 0.012)^{4t}$ $Compound\quaterly\ interest = P_{0} (1.012)^{4t}$

Now also calculated monthly.

Formula

$Compound\ monthly = Principle (1 + \frac{r}{12})^{12t}$

As given

$Take\ Principle\ = P_{0}$

$Rate = \frac{4.8}{100}$

= 0.048

Put in the formula

$Compound\ monthly = P_{0} (1 + \frac{0.048}{12})^{12t}$

$Compound\ monthly = P_{0} (1 + 0.004)^{12t}$

$Compound\ monthly = P_{0} (1.004)^{12t}$

As the approximation quarterly growth rate of the value of sean's house is near the Compounded quarterly interest .

Thus Option (A) is correct.

i.e

The expression $(1.0118)^{4t}$ reveals the approximate quarterly growth rate of the value of Sean's house.

6 0

3 years ago

Read 2 more answers

If x = a cosθ and y = b sinθ , find second derivative

Olin [163]

I'm guessing the second derivative is for y with respect to x, i.e.

$\dfrac{\mathrm d^2y}{\mathrm dx^2}$

Compute the first derivative. By the chain rule,

$\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{\mathrm dy}{\mathrm d\theta}\dfrac{\mathrm d\theta}{\mathrm dx}=\dfrac{\frac{\mathrm dy}{\mathrm d\theta}}{\frac{\mathrm dx}{\mathrm d\theta}}$

We have

$y=b\sin\theta\implies\dfrac{\mathrm dy}{\mathrm d\theta}=b\cos\theta$

$x=a\cos\theta\implies\dfrac{\mathrm dx}{\mathrm d\theta}=-a\sin\theta$

and so

$\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{b\cos\theta}{-a\sin\theta}=-\dfrac ba\cot\theta$

Now compute the second derivative. Notice that $\frac{\mathrm dy}{\mathrm dx}$ is a function of $\theta$ ; so denote it by $f(\theta)$ . Then

$\dfrac{\mathrm d^2y}{\mathrm dx^2}=\dfrac{\mathrm df}{\mathrm dx}$

By the chain rule,

$\dfrac{\mathrm d^2y}{\mathrm dx^2}=\dfrac{\mathrm df}{\mathrm d\theta}\dfrac{\mathrm d\theta}{\mathrm dx}=\dfrac{\frac{\mathrm df}{\mathrm d\theta}}{\frac{\mathrm dx}{\mathrm d\theta}}$