2 x - 5 y = 18 / * 4
3 x + 4 y = 4 / * 5 ( we will use the addition method )
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8 x - 20 y = 72
+
15 x + 20 y = 20
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23 x = 92
x = 92 : 23
x = 4
8 - 5 y = 18
- 5 y = 18 - 8
- 5 y = 10
y = 10 : ( - 5 )
y = - 2
Answer:
( x, y ) = ( 4, - 2 )