SOLUTION: 5s-2t-1=-a -8s+bt-2=2 In the system of equations above a and b are constants. If the system has infinitely many solutions, what is the value of a?

Algebra ->  Systems-of-equations -> SOLUTION: 5s-2t-1=-a -8s+bt-2=2 In the system of equations above a and b are constants. If the system has infinitely many solutions, what is the value of a?      Log On


   

Question 1041044: 5s-2t-1=-a
-8s+bt-2=2
In the system of equations above a and b are constants. If the system has infinitely many solutions, what is the value of a?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
5s-2t=1-a
-8s%2Bbt=4
If they have infinitely many solutions then the first equation is a multiple of the second.
5s-2t=alpha%28-8s%2Bbt%29
and
1-a=alpha%284%29
Using the coefficient for s,
5s=alpha%28-8s%29
alpha=-5%2F8
So then,
1-a=%28-5%2F8%294
1-a=-5%2F2
a=1%2B5%2F2
highlight%28a=7%2F2%29