Question

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Answer 1

A) x - y = 5 ⇒ x = 5 + y

5 + y +3y = 9
y = 4/4 = 1

x = 5 + 1 = 6

B) 3x -2y = 6 ⇒ x = 2 + y

x - 3y = 2 
2 + y -3y = 2
-2y = 2 - 2 (.-1)
y = 0

x = 2

C) x + y = 4 ⇒ x = 4 - y

2 (4-y) +y = 7
8 -2y +y = 7
-y = 7 - 8 (.-1)
y = 1

x = 4 -1
x = 3