Solve the system of equations y=x-7 y=x^2-9x+18

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  (x, y) = (5, -2)

Step-by-step explanation:

Equating expressions for y, we have ...

  x^2 -9x +18 = x -7

  x^2 -10x +25 = 0 . . . . . add 7-x to both sides

  (x -5)^2 = 0 . . . . . . . . factor

The value of x that makes the factor(s) zero is x=5. The corresponding value of y is ...

  y = x -7 = 5 -7 = -2

The solution is (x, y) = (5, -2).