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x-4y=2
-2x-5y=9
solve equations by substitution
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x - 4y = 2, (1)
-2x - 5y = 9. (2)
From (1), express x = 2 + 4y and substitute it into (2). You will get a single equation for y:
-2*(2+4y) - 5y = 9.
Simplify and solve for y:
-4 - 8y - 5y = 9,
-13y = 9 + 4,
-13y = 13,
y = -1.
Then x = 2 + 4y = 2 + 4*(-1) = 2 - 4 = -2.
Answer. x = -2, y = -1.