What real values of x are not in the domain of f(x) = 1/((x^2 + 3x - 4)*(x^2 + 9x + 20))?
1
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(x^2 + 3x - 4) (x^2 + 9x + 20)
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( x + 4)(x - 1) (x + 5) ( x + 4)
The denominator cannot = 0..... so
x = -5 x = -4 and x = 1 are not in the domain