Answer:

Step-by-step explanation:
The future value formula is FV=PV(1+i)^n, where the present value PV increases for each period into the future by a factor of 1 + i. value PV increases for each period into the future by a factor of 1 + i.

fv = future value
pv = present value
r = annual interest rate ( decimal number)
n= period
x = 
subtract 4x from both sides of the equation
6x - 4x - 2 = 13
2x - 2 = 13
add 2 to both sides
2x = 13 + 2 = 15
divide both sides by 2
x = 
So you know that:
2x+y=14+y
and
5x-y=x+13y
Here you have two equations with two unknown variables:
If you isolate x from the second equations you get:
x=(7/2)y
Insert that in the first equations and solve for y:
2*(7/2)y+y=14+y
y=2
Insert that value for y in one of the two equations (i chose the first):
2x+2=14+2
x=7
Therefore x=7
Hope that helped.
Actually you could start with isolating x, and then insert that in one of the two equations.
If you distribute -4 through (5k-7), it equals -20k + 28. Then put on the other -2k on that side of the equals sign and you should have -22k + 28 = -2(9k+5) Then you need to distribute -2 through (9k+5) which equals -18k - 10. You then should have -22k+28=-18k-10. Add 22k to both sides to cancel it out, then you should have 28=4k-10. Add 10 to both sides to get the 4k by itself, which will be 38=4k, then divide both sides by 4 to get k by itself. 38/4 = 19/2. k = 19/2