Answer:
(-1,10)
Step-by-step explanation:
At the point when the paths cross, the respective x and y values of each equation will be equal.
Your path is y=2x+12, and your friends path is 4x+y=6. Sub 2x+12 in for y (from your path's equation) into your friends equation to find the value of x:
4x+2x+12=6
6x=-6
x=-1
y=2x+12
y=2(-1)+12=10
So you will cross paths at (-1,10)
You do 2x20 which is basically 2x2 (4) add a zero and your answer is 40
Answer:
the answer to this question is 120km/hr
Answer:

Since the measurement can't be negative the correct answer for this case would be 
Step-by-step explanation:
Let's assume that the figure attached illustrate the situation.
For this case the we know that the original area given by:

And we know that the initial area is a half of the entire area in red
, so then:

And we know that the area for a rectangular pieces is the length multiplied by the width so we have this:

We multiply both terms using algebra and the distributive property and we got:

And we can rewrite the expression like this:

And we can solve this using the quadratic formula given by:

Where
if we replace we got:

And the two possible solutions are then:

Since the measurement can't be negative the correct answer for this case would be 
9514 1404 393
Answer:
21.25 seconds
Step-by-step explanation:
In miles per second, the speed of the jet is ...
(720 mi/h)/(3600 s/h) = 1/5 mi/s
The speed of the sound is the same:
(1 mi)/(5 s) = 1/5 mi/s
Then the rate of closure between the airplane and the sound is ...
(1/5 mi/s) +(1/5 mi/s) = 2/5 mi/s
To find the time required to close a gap of 8 1/2 miles, we can use the relation ...
time = distance/speed
time = (8.5 mi)/(0.4 mi/s) = 21.25 s
The pilot will hear the thunder 21.25 seconds after the flash.