Answer:
x = 1.6 , y = 13.8
Step-by-step explanation:
y - 3x = 9 ( add 3x to both sides )
y = 9 + 3x → (1)
7x + y = 25 → (2)
Substitute y = 9 + 3x into (2)
7x + 9 + 3x = 25
10x + 9 = 25 ( subtract 9 from both sides )
10x = 16 ( divide both sides by 10 )
x = 1.6
Substitute x = 1.6 into (1)
y = 9 + 3(1.6) = 9 + 4.8 = 13.8