2.1(0.2x−1.4)=1.3(0.4x−3.5) 25 points on the line plz help

from the edge of a 486-foot cliff, peyton shot an arrow over the ocean with an initial upward velocity of 90-feet per second

anygoal [31]

Answer:

9 seconds

Step-by-step explanation:

The complete question is

The altitude of an object, d, can be modeled using the equation below:

d=-16t^2 +vt+h

from the edge of a 486 foot cliff, Peyton shot an arrow over the ocean with an initial upward velocity of 90 feet per second. In how many seconds will the arrow reach the water below?

Let

d ----> the altitude of an object in feet

t ---> the time in seconds

v ---> initial velocity in ft per second

h ---> initial height of an object in feet

we have

$d=-16t^2 +vt+h$

we know that

When the arrow reach the water the value of d is equal to zero

we have

$v=90\ ft/sec$

$h=486\ ft$

$d=0\ ft$

substitute the values and solve for t

$0=-16t^2 +(90)t+486$

$-16t^2+90t+486=0$

Multiply by -1 both sides

$16t^2-90t-486=0$

The formula to solve a quadratic equation of the form $ax^{2} +bx+c=0$ is equal to

$x=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}$

in this problem we have

$a=16\\b=-90\\c=-486$

substitute in the formula

$t=\frac{90(+/-)\sqrt{-90^{2}-4(16)(-486)}}{2(16)}$

$t=\frac{90(+/-)\sqrt{39,204}}{32}$

$t=\frac{90(+/-)198}{32}$

$t_1=\frac{90(+)198}{32}=9\ sec$

$t_2=\frac{90(-)198}{32}=-3.375\ sec$

the solution is t=9 sec

see the attached figure to better understand the problem

4 0

2 years ago

Ms Rochelle wants to put her 29 students into 6 groups

slamgirl [31]

She needs 4 groups at the most, having 6 kids leftover, 6×4=24, not that hard

3 0

3 years ago

Read 2 more answers

A fair coin and a biased coin where the probability of obtaining a head is twice the probability of obtaining a tail. if both ar

Art [367]

Answer:

See below in bold.

Step-by-step explanation:

For the fair coin Prob(head) = 1/2 and Prob(Tail) = 1/2.

For the biased coin it is Prob(head) = 2/3 and Prob(Tail) = 1/3.

a) Prob(2 heads) = 1/2 * 2/3 = 1/3.

b) Prob(2 tails) = 1/2 * 1/3 = 1/6.

c) Prob(1 head ) = Prob(H T or T H) = 1/2 * 1/3 + 1/2 * 2/3) = 1/6+1/3 = 1/2.

d) Prob (at least one head) = prob (HH or TH or HT) = 1/3 + 1/2 = 5/6.

4 0

3 years ago

7.Suppose that water is entering a cylindrical water tank so that the initial height of the water is 3 cm and the

lukranit [14]

Answer:

$H(t) = 3*2^{t/30}$

Step-by-step explanation:

Height doubles at every 30 seconds, so let's call n how many times it happens, and the t the total time:

n = t/30

If the height doubles one time, it is multiplied by 2, if it doubles 2 times, it's multiplied by 2², for n times, it is multiplied by 2ⁿ, so for an initial height equal to 3:

$H(t) = 3*2^{t/30}$

4 0

2 years ago

The number of decimal places in the product will be sum of the factor"s decimal place.So the product will have 1,2,3 or 4 decima

vampirchik [111]

Answer:

$0.47 \to 2\ digits$