Since one equation has a negative y and the other has a positive y, I'm going to use those since they cancel each other out. Before that, the two y's need to be equal to each other.
x+2y=6
x-y=3
Multiply the bottom equation by two so then you have:
x+2y=6
2x-2y=6
The y's now cancel out:
x=6
2x=6
Add them together
3x=12
Divide
x=4.
To find y, plug x into either equation (*don't have to do both, but I will)
(4)+2y=6
(4)-y=3
Subtract four
2y=2
-y=-1
Divide each
2y/2 = 2/2
y=1
-y/-1 = -1/-1
y=1
The answer is:
x=4
y=1
I hope that helps!
Answer:
15/322
Step-by-step explanation:
There are 12 tests of test A, and there are 12 tests of test B.
For the student to get A, it is a 12/24 chance.
For the next student, it is a 11/23 chance
For the next 10/22
For the next 9/21
12/24*11/23*10/22*9/21=15/322
15/322 chance
F(x) = x² - 10x - 4
f(x) + 4 = x² - 10x
- 10x / 2 = - 5x
- 5² = 25
f(x) + 4 + 25 = (x² - 10x + 25)
f(x) + 29 = (x-5)²
f(x) = (x-5)² - 29
D. 25
Answer:
Given,
Distance traveled = 20 km
Speed = 60 km/h
So, timetaken=DistanceSpeed=2060=13h
For the next journey
Distance traveled = 20 km
Speed = 80 km/h
So, timetaken=DistanceSpeed=2080=14h
Now,
Total distance traveled = 20 + 20 = 40 km
Total time taken = 13+14=712
We know,
Averagespeed=TotaldistancetraveledTotaltimetaken=40712=68.5 km/h
Hence the average speed of the train is 68.5 km/h