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Answer:
(x, y) = (-3, -6)
Step-by-step explanation:
The second equation can be used to write an expression for y:
... -5x -21 = y . . . . . . . add y-21 to both sides
This expression can be substituted for y in the first equation:
... 6 = -4x +(-5x -21)
... 27 = -9x . . . . . add 21, collect terms
... -3 = x . . . . . . . divide by -9
Using this value of x in the expression for y, we find ...
... -5(-3) -21 = y = -6
The solution is x = -3, y = -6.
