Answer:
s = -2
t = 1
Explanation:
If such scalars exist, they must be the solutions to the equations ...
5s +t = -9
-3s -t = 5
Adding these equations gives ...
2s = -4
s = -2
Filling in the first equation, we can solve for t:
5(-2) +t = -9
t = 1 . . . . add 10
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As a check on these values, we try them for all three vector components:
-2<5, -3, 0> +1<1, -1, 5> = <-2(5)+1, -2(-3)-1, -2(0)+5> = <9, 5, 5>
as required.
The scalars s and t are (s, t) = (-2, 1).