SOLUTION: 3t - r = 9 r = 2t + 8 i am a parent trying to show my child how to do this and i need to know how to do it step by step. i can look at it and figure out some of it but need to

Question 159253This question is from textbook Holt Algebra 2
: 3t - r = 9
r = 2t + 8
i am a parent trying to show my child how to do this and i need to know how to do it step by step. i can look at it and figure out some of it but need to know what to do first, second, etc. This question is from textbook Holt Algebra 2

Answer by t_as87(5) (Show Source): You can put this solution on YOUR website!
3t - r = 9
r = 2t + 8
You have 2 equations, with 2 unknowns r and t...
the second equation can be used to substitute the value of r in the first equation, so we get a new equation with the form:
3t - (2t + 8) = 9
Now we can solve for t
t - 8 = 9
t = 17
We now know what the value of t is. We can substitute this value in the second equation to get a value for r
r = 2(17) + 8
so r = 42
t = 17, r = 42
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