Question 17601
This one is easier than it looks.  First look at the second equation.  You can see by looking at this equation that {{{t= -4}}}.


Knowing that t=-4, solve for s in the third equation:  
6s+5t= 10
6s+5(-4) = 10
6s-20=10
6s=30
s=5


Knowing that s=5, solve for r in the first equation:
5r + 2s=0
5r+2(5)=0
5r +10=0
5r= -10
r=-2


(r,s,t) = (-2, 5. -4)


R^2 at SCC