Alright...simple...showing all steps.. ;)
You have the equations...
2x+y=7
and
3x+5y=14
To be able to even solve for any of the variables...multiply the equations by...2...and..3...
2x+y=7----*3--> 6x+3y=21
and
3x+5y=14-----*2--->6x+10y=28
Thus,
6x+3y=21
-
6x+10y=28
=========
-7y=-7
y=1
Now, plug y back into any of the original equations....we'll use 2x+y=7 in this case....
2x+(1)=7
2x+1=7
-1 -1
2x=6
x=3
Thus, the point of intersection for these two equations is (3,1)
Well 1000 for his birthday then subtract 25 each week, w, should be 1000-25w if i am not mistaken.
Try this solution:
Answer: 6 & 4.5 (m-per-h)
Step-by-step explanation:
- The basic formula used in this task is S=V*t, where S - distance, V - speed, t - time.
- the downstream speed is: V+Vc, where V - the speed of the boat in still water, Vc - the speed of the current.
- the upstream speed is: V-Vc.
- according to the described above the distance for downstream is S1=(V+Vc)*t1, where t1=10; the distance for upstream is S2=(V-Vc)*t2, where t2=70.
- for whole travel down- and upstream: S=S1+S2.
- Using these it is possible to make up the system of the equations:
V - the speed of the boat in still water - 6 miles per hour, Vc - the speed of the current - 4.5 miles per hour. All the details for the system of the equations are in the attachment.
Answer:
7 wrong answers.
Step-by-step explanation:
We know that when you answer a question well, you earn 8 points and a bad one loses 5 points, this means that when you answer 1 good and 1 bad, there is a total of 3 points (8-5).
This means that when answering 5 good and 5 bad, in total it would be 3 * 5 points, that is to say 15 points, that is, it goes through 2 points. To subtract 2 points, you would have to answer 1 good and 2 bad, (8 - 2 * 5), which turns out to be -2 points.
In total there would be 6 questions right and 7 questions wrong, like this:
8 * 6 + 5 * 7 = 13
13 points, in 13 questions (6 correct + 7 incorrect)
The rest of the questions were not answered so that the score does not go up or down.
Which means you got 7 wrong answers.
