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3 years ago

jack is 4 times as old as lacy. 9 years from now the sum of their ages will be 68. how old are they now?

2 answers:

5 0

The answer is 12.
since we also know that jack is 2 times lucy now then the entire formula would be 2x - 6 = 18 to solve we add 6 to both sides 2x - 6 + 6 = 18 + 6 the 6s on the left cancel because when you have a positive and negative of the same number it always = 0 we get 2x = 24 then divide both sides by 2 to get the answer 2x / 2 = 24 / 2 the 2s on the left cancel and you get

Lyrx [107]3 years ago

4 0

J=4L, (J+9)+(L+9)=68 using J=4L in the second equation gives you:

4L+9+L+9=68

5L+18=68

5L=50

L=10 and since J=4L

J=40

So Jack is 40 years old and Lacy is 10 years old.

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V= 2i +9j Find ||9v||

Korvikt [17]

Answer:

9 $\sqrt{85}$

Step-by-step explanation:

9v = 9(2i + 9j) = 18i + 81j

|9v | = $\sqrt{18^2+81^2}$ = $\sqrt{x6885}$ = 9 $\sqrt{85}$

8 0

2 years ago

Which is the range of the function f(x) =1/7(9)x? all real numbers all real numbers less than 0 all real numbers greater than 0

zimovet [89]

I cannot suggest anything other than the set of real numbers here, but maybe someone else can provide a better answer. As long as you increase or decrease x (which is a real number) then you will get a real number, or the infinite set of real numbers.

4 0

2 years ago

Read 2 more answers

If a ball is thrown straight up into the air with an initial velocity of 70 ft/s, its height in feet after t seconds is given by

Vitek1552 [10]

Answer:

a) Average velocity at 0.1 s is 696 ft/s.

b) Average velocity at 0.01 s is 7536 ft/s.

c) Average velocity at 0.001 s is 75936 ft/s.

Step-by-step explanation:

Given : If a ball is thrown straight up into the air with an initial velocity of 70 ft/s, its height in feet after t seconds is given by $y = 70t-16t^2$ .

To find : The average velocity for the time period beginning when t = 2 and lasting. a. 0.1 s. , b. 0.01 s. , c. 0.001 s.

Solution :

a) The average velocity for the time period beginning when t = 2 and lasting 0.1 s.

$(\text{Average velocity})_{0.1\ s}=\frac{\text{Change in height}}{0.1}$

$(\text{Average velocity})_{0.1\ s}=\frac{h_{2.1}-h_2}{0.1}$

$(\text{Average velocity})_{0.1\ s}=\frac{(70(2.1)-16(2.1)^2)-(70(0.1)-16(0.1)^2)}{0.1}$

$(\text{Average velocity})_{0.1\ s}=\frac{69.6}{0.1}$

$(\text{Average velocity})_{0.1\ s}=696\ ft/s$

b) The average velocity for the time period beginning when t = 2 and lasting 0.01 s.

$(\text{Average velocity})_{0.01\ s}=\frac{\text{Change in height}}{0.01}$

$(\text{Average velocity})_{0.01\ s}=\frac{h_{2.01}-h_2}{0.01}$

$(\text{Average velocity})_{0.01\ s}=\frac{(70(2.01)-16(2.01)^2)-(70(0.01)-16(0.01)^2)}{0.01}$

$(\text{Average velocity})_{0.01\ s}=\frac{75.36}{0.01}$

$(\text{Average velocity})_{0.01\ s}=7536\ ft/s$

c) The average velocity for the time period beginning when t = 2 and lasting 0.001 s.

$(\text{Average velocity})_{0.001\ s}=\frac{\text{Change in height}}{0.001}$

$(\text{Average velocity})_{0.001\ s}=\frac{h_{2.001}-h_2}{0.001}$

$(\text{Average velocity})_{0.001\ s}=\frac{(70(2.001)-16(2.001)^2)-(70(0.001)-16(0.001)^2)}{0.001}$

$(\text{Average velocity})_{0.001\ s}=\frac{75.936}{0.001}$

$(\text{Average velocity})_{0.001\ s}=75936\ ft/s$

5 0

3 years ago

Prii needs to run at least 30

frozen [14]

30 - 18 = 12
So he has 12 miles left for this week.
There are 3 more days
So 12 divided by 3
Which is 4, so he needs 3 more hours per day for the remaining 3 days

7 0

2 years ago

What is the principal value cost of cos−1<br> (0.69)

CaHeK987 [17]

We are asked to find the principal value of
cos ⁻¹ (0.69)
which is just the least positive angle
cos ⁻¹ (0.69) = 46.37°
Other values of
cos ⁻¹ (0.69) is
46.37° - 180° n
where n is a whole number

6 0

3 years ago