Answer:
The given system of equations has solutions below:
1) The solution is (2,3)
2) The solution is (
)
3) The solution is infinitely many solutions
4) No solution
Step-by-step explanation:
Given system of equation are


To solve equation by using elimination method
Multiply eqn (2) into 2

Now subtracting (1) and (3)


_________________
7x=14
x=

Substitute x=2 in equation (1)
-2+2y=4
2y=4+2

y=3
Therefore the solution is (2,3)
2) Given equation is

4y-4=x
Rewritting as below

To solve equation by using elimination method
multiply (2) into 2

Adding (1) and (3)
-2x+y=3
2x-8y=-8
________
-7y=-5

substitute
in (1)




Therefore the solution is (
)
3) Given equation is 

equation (1) can be written as
2(3x+y)=10

3x+y=5
Therefore equations (1) and (2) are same therefore it has infinitely many solutions
4) Given equation is 

multiply equation (1) into 2

To solve equation by using elimination method
subtracting (2) and (3)
-2x-4y=28
-2x-4y=12
_______

therefore it has no solution
<span>You run 0.5 miles every 3 minutes => 1 mile every 6 minutes. Your friend runs 2 miles every 14 minutes => 1 mile every 7 minutes. You run a whole number of miles every number of minutes that is a multiple of 6. Your freind runs a whole number of miles every number of minutes that is a multiple of 7 Then the least possible number of miles that you both run to end at the same time is the least common factor of 7 and 6 minutes. This is 7 * 6 = 42 minutes. You will have run 42 min / (6 miles/min) = 7 miles, and your friend will have run 42 min / (7 miles/min) = 6 miles</span>
14n=-126
/14 /14 divide by 14 on both sides of the
equation
n=-9
Their frequency stays the same and their wavelength decreases