Factor completely x2 − 36. (1 point)

Kirby is four miles from the train station, from which a train is due to leave in 56 minutes. Kirby is walking along at 3 mph, a

Luda [366]

Let's assume that Kirby walks with a speed
$v_1 = 3 mph$
for a time $t_1$ , and that he runs with a speed
$v_2 = 12 mph$
for a time $t_2$ .

The total time available for Kirby to catch the train is:
$t=56 min = 0.93 h$
and this must be equal to the sum of the two times t1 and t2:
$0.93 = t_1 + t_2$

The distance Kirby should cover is
$S=4 m$
and this should be equal to the sum of the distances covered by walking and by running:
$4 = S_1 + S_2 = v_1 t_1 + v_2 t_2 = 3 t_1 + 12 t_2$

So we have a system of 2 equations:
$0.93 = t_1 + t_2$
$4 = 3 t_1 + 12 t_2$

If we solve the system, we find:
$t_1 = 0.80 h = 48 min$
$t_2 = 0.13 h = 8 min$

So, Kirby needs to run at least for 8 minutes in order to catch the train.

6 0

3 years ago

1) Write an equation in slope-intercept form of the line with slope of 6 and y-intercept of -3. Then graph the line. 2) Write an

asambeis [7]

Answer:

An equation in the slope-intercept form is:

y = a*x + b

Where a is the slope, and b is the y-intercept.

a)

Here we have a slope of 6 and a y-intercept of -3

Then the equation is:

y = 6*x - 3

Now we want to graph this.

To graph it, we first need to find two points (x, y) that belong to this equation, then we can graph the points, and connect them with a line.

To find the points, we evaluate in two different values of x.

x = 0

y = 6*0 - 3 = -3

Then we have the point (0, -3)

x = 1

y = 6*1 - 3 = 3

Then we have the point (1, 3)

The graph of this line can be seen in the image below (the red one)

b) Similar to before, here the slope is -3/5, then the equation is something like:

y = (-3/5)*x + b

Now we also know that the line passes through the point (-10, 8)

This means that when x = -10, we must have y = 8

Replacing these two in the equation we get:

8 = (-3/5)*-10 + b

8 = 6 + b

8 - 6 = 2 = b

Then this equation is:

y = (-3/5)*X + 2

The graph can be found in the same way as before, the graph of this function can also be seen in the image below (the green one)

6 0

3 years ago

(Functions and Relations) Answer getting brainliest! Explain if you can ^^

hodyreva [135]

Answer:

C

Step-by-step explanation:

Have a nice day :)

when you can plz give me brainllest

6 0

3 years ago

-1/2(x+4)=y-2 2x-y=4 Find the slope, x-intercept, and y-intercept for both equations

FinnZ [79.3K]

Answer:

Step-by-step explanation:

slope of a linear equation is m = y2 -y1/x2-x1

x- intercept, is where y = 0

y- intercept is where x = 0

7 0

3 years ago

A countrys population in 1990 was 145 million. In 1998 it was 151 million. Estimate the population in 2015 using the exponential

alexandr402 [8]

Answer:

The population in 2015 will be 165 million.

Step-by-step explanation:

The exponential growth formula is given by:

$f(t) = a(1 + r)^{\Delta t}$

Where:

a: is the initial population

r: is the rate of increase

Δt: is the time

With the initial information we can find the rate:

$151 = 145(1 + r)^{1998-1990}$

Using logarithm:

$ln(151) = ln(145) + 8[ln(1 + r)]$

$ln(1 + r) = \frac{ln(151) - ln(145)}{8}$

$ln(1 + r) = 5.0683 \cdot 10^{-3}$

Using exponential:

$e^{ln(1 + r)} = e^{5.0683 \cdot 10^{-3}}$

$r = 5.081 \cdot 10^{-3}$

Now, we can find the estimated population in 2015:

$f(t) = 151(1 + 5.081 \cdot 10^{-3})^{2015-1998}$

$f(t) = 165$

Therefore, the population in 2015 will be 165 million.

I hope it helps you!

5 0

3 years ago