SOLUTION: Solve each system by substitution: [r+3s=9 [3r+2s=13

Algebra ->  Expressions-with-variables -> SOLUTION: Solve each system by substitution: [r+3s=9 [3r+2s=13      Log On


   



Question 164488: Solve each system by substitution:
[r+3s=9
[3r+2s=13

Answer by midwood_trail(310) About Me  (Show Source):
You can put this solution on YOUR website!
Solve each system by substitution:
[r+3s=9
[3r+2s=13

Let [r+3s=9 be Equation A
Let [3r+2s=13 be Equation B
I will solve for r in Equation A.
r + 3s = 9
r = -3s + 9
I will now plug this "value" for r into Equation B and solve for s.

3(-3s + 9) + 2s = 13
-9s + 27 = 13
-9s = -27 + 13
-9s = -14
s = -14/-9
s = 14/9....This is the true value of s.
Now, to find r, replace s with 14/9 in EITHER Equation A or B (your choice which equation) and then simplify.
Can you take it from here?
If not, write back.