What's the standard form of eight three million, twenty three thousand,seven

The number of new cars purchased in a city can be modeled by the equation C=20t to the 2nd power, where C is the number of new c

Allisa [31]

Answer:

$1998 + 5\sqrt{30}$

Step-by-step explanation:

Set up the equation:

Since C(t) gives the number of cars purchased in the t-th year after 1998, then make the number of cars equal to 15 000 and solve for t - the year:

20t^2 = 15000

t^2 = 750

t = $\sqrt{750} = \sqrt{10} \cdot \sqrt{25} \cdot \sqrt{3} = 5\sqrt{30}$

The year will be simply 1998 + 5 \sqrt{30}

4 0

3 years ago

Rewrite the expression with rational exponents as a radical expression.

nexus9112 [7]

Answer:

If the expression is $4x^\frac{3}{7}$ , then the answer is the first option.

If the expression is $(4x)^\frac{3}{7}$ , then the answer is the third option.

Step-by-step explanation:

Remember that when you have a radical expression in the form $\sqrt[n]{x}$ , you can rewrite as:

$=x^\frac{1}{n}$

Then:

- If the expression is $4x^\frac{3}{7}$ , then you can rewrite it in the following radical form:

$=4\sqrt[7]{x^3}$ (This form matches with the first option.)

- If the expression is $(4x)^\frac{3}{7}$ , then you can rewrite it in the following radical form:

$=\sqrt[7]{(4x)^3}$ (This form matches with the third option).

7 0

3 years ago

Read 2 more answers

How is this solved using trig identities (sum/difference)?

GenaCL600 [577]

FIRST PART
We need to find sin α, cos α, and cos β, tan β
α and β is located on third quadrant, sin α, cos α, and sin β, cos β are negative

Determine ratio of ∠α
Use the help of right triangle figure to find the ratio
tan α = 5/12
side in front of the angle/ side adjacent to the angle = 5/12
Draw the figure, see image attached

Using pythagorean theorem, we find the length of the hypotenuse is 13
sin α = side in front of the angle / hypotenuse
sin α = -12/13

cos α = side adjacent to the angle / hypotenuse
cos α = -5/13

Determine ratio of ∠β
sin β = -1/2
sin β = sin 210° (third quadrant)
β = 210°

$cos \beta = -\frac{1}{2} \sqrt{3}$

$tan \beta= \frac{1}{3} \sqrt{3}$

SECOND PART
Solve the questions
Find sin (α + β)
sin (α + β) = sin α cos β + cos α sin β
$sin( \alpha + \beta )=(- \frac{12}{13} )( -\frac{1}{2} \sqrt{3})+( -\frac{5}{13} )( -\frac{1}{2} )$
$sin( \alpha + \beta )=(\frac{12}{26}\sqrt{3})+( \frac{5}{26} )$
$sin( \alpha + \beta )=(\frac{5+12\sqrt{3}}{26})$

Find cos (α - β)
cos (α - β) = cos α cos β + sin α sin β
$cos( \alpha + \beta )=(- \frac{5}{13} )( -\frac{1}{2} \sqrt{3})+( -\frac{12}{13} )( -\frac{1}{2} )$
$cos( \alpha + \beta )=(\frac{5}{26} \sqrt{3})+( \frac{12}{26} )$
$cos( \alpha + \beta )=(\frac{5\sqrt{3}+12}{26} )$

Find tan (α - β)
$tan( \alpha - \beta )= \frac{ tan \alpha-tan \beta }{1+tan \alpha tan \beta }$
$tan( \alpha - \beta )= \frac{ \frac{5}{12} - \frac{1}{2} \sqrt{3} }{1+(\frac{5}{12}) ( \frac{1}{2} \sqrt{3})}$

Simplify the denominator
$tan( \alpha - \beta )= \frac{ \frac{5}{12} - \frac{1}{2} \sqrt{3} }{1+(\frac{5\sqrt{3}}{24})}$
$tan( \alpha - \beta )= \frac{ \frac{5}{12} - \frac{1}{2} \sqrt{3} }{ \frac{24+5\sqrt{3}}{24} }$

Simplify the numerator
$tan( \alpha - \beta )= \frac{ \frac{5}{12} - \frac{6}{12} \sqrt{3} }{ \frac{24+5\sqrt{3}}{24} }$
$tan( \alpha - \beta )= \frac{ \frac{5-6\sqrt{3}}{12} }{ \frac{24+5\sqrt{3}}{24} }$

Simplify the fraction
$tan( \alpha - \beta )= (\frac{5-6\sqrt{3}}{12} })({ \frac{24}{24+5\sqrt{3}})$
$tan( \alpha - \beta )= \frac{10-12\sqrt{3} }{ 24+5\sqrt{3}}$

7 0

3 years ago

The price of a pair of jeans was $60 after a 50% markup. What was the price of the jeans before the markup?

zhenek [66]

Answer:

40

Step-by-step explanation:

We have an original price p

We mark them up by 50%

p + p*50%

Changing to decimal form

p+.50p = 1.5p

The new price is 60 dollars

1.5p = 60

Divide each side by 1.5

1.5p/1.5 = 60/1.5

p =40

The original price is 40

5 0

3 years ago

Read 2 more answers

(a) Use the fundamental theorem of algebra to determine the number of roots for 2x^2 + 4x + 7

zysi [14]

Answer:

Step-by-step explanation:

A 2nd order polynomial such as this one will have 2 roots; a 3rd order polynomial 3 roots, and so on.

The quadratic formula is one of the faster ways (in this situation, at least) in which to find the roots. From 2x^2 + 4x + 7 we get a = 2, b = 4 and c = 7.

Then the discriminant is b^2 - 4ac, or, here, 4^2 - 4(2)(7), or -40. Because the discriminant is negative, we know that the roots will be complex and unequal.

Using the quadratic formula:

-4 ±√[-40] -4 ± 2i√10

x = ------------------ = ------------------

4 4

-2 ± i√10

Thus, the roots are x = ------------------

2

4 0

3 years ago