Help me with this please

First examples pt 1 no one answer

andrew11 [14]

Answer:

It takes the second worker 11 hours to do the job alone

Step-by-step explanation:

The problem tells you how to work it.

$\dfrac{1}{11}+\dfrac{1}{x}=\dfrac{2}{11}\\\\x+11=2x \qquad\text{multiply by 11x}\\\\11=x \qquad\text{subtract x}$

x = 11 tells you the second worker takes 11 hours to do the job alone.

_____

You can also work directly with the fractions. Subtract 1/11 and you have ...

1/x = 1/11

It should not be a real stretch to see that x=11. If you need, you can multiply both sides by 11x to get 11=x.

3 0

2 years ago

PLEASE HELP<br> find the vertex of f(x)=x^2+2x+3 (make sure you show your work)

kotegsom [21]

Answer:

(- 1, 2)

Step-by-step explanation:

Given a quadratic in standard form y = ax² + bx + c : a ≠ 0

Then the x- coordinate of the vertex is

$x_{vertex}$ = - $\frac{b}{2a}$

f(x) = x² + 2x + 3 ← is in standard form

with a = 1 and b = 2, hence

$x_{vertex}$ = - $\frac{2}{2}$ = - 1

Substitute x = - 1 into f(x) for corresponding value of y

f(- 1) = (- 1)² + 2(- 1) + 3 = 1 - 2 + 3 = 2

vertex = (- 1, 2 )

4 0

2 years ago

For a finite sequence of nonzero numbers, the number of variations in sign is defined as the number of pairs of consecutive term

elena55 [62]

Answer:

The no. of variations in sign is 3

Step-by-step explanation:

Variation in sign occurs when every single time a negative product is produced by a pair of consecutive terms.

Therefore, the determination of the number of changes in sign in the given sequence is must.

Therefore, we take the product of the pair of consecutive terms as:

$1\times (-3)$ = - 3, variation in sign

$(-3)\times 2$ = - 6, variation in sign

$2\times 5$ = 10, no sign variation

$5\times (- 4)$ = - 20, variation in sign

$- 4\times (-6)$ = 24, no sign variation

7 0

2 years ago

A sum of money is deposited at a bank at a rate of 12½ annum simple interest. In how many years would the deposited money be dou

Dmitrij [34]

Answer:

It would take 10 years for the given sum of money be doubled at the given simple interest rate.

Step-by-step explanation:

A 10% interest would be added to the the principal amount after each year. So the interest would reach 100% i.e. equal to the principal amount in 10 years.

7 0

2 years ago

Choose the correct graph of the function y=-1/2√x+3+2

Bad White [126]

Find y intercept

$\\ \rm\rightarrowtail y=-\dfrac{1}{2}\sqrt{x+3}+2$

$\\ \rm\rightarrowtail y=-\dfrac{1}{2}\sqrt{0+3}+2$

$\\ \rm\rightarrowtail y=\dfrac{-\sqrt{3}}{2}+2$

$\\ \rm\rightarrowtail y=\dfrac{4-\sqrt{3}}{2}$

$\\ \rm\rightarrowtail y=\dfrac{4-1.732}{2}$

$\\ \rm\rightarrowtail y=\dfrac{2.368}{2}$

$\\ \rm\rightarrowtail y=1.184$

y intercept=(0,1.2)

Option A

5 0

1 year ago