Answer:
Step-by-step explanation:
-5x + 3y = 21
-5x - 9y = -3.....multiply by -1
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-5x + 3y = 21
5x + 9y = 3 (result of multiplying by -1)
-------------------add
12y = 24
y = 24/12
y = 2
-5x + 3y = 21
-5x + 3(2) = 21
-5x + 6 = 21
-5x = 21 - 6
-5x = 15
x = -15/5
x = -3
solution is : x = -3 and y = 2...or (-3,2)
