There are no two real numbers that do so, but the two complex numbers which do so are:
11/2 + i√47/2 and 11/2 - i√47/2
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If you meant what two number have a product of -42 (ie NEGATIVE 42) and a sum of 11, then the two numbers are 14 and -3 Or a product of -42 and a sum of -11 (negative 11), then the two numbers are -14 and 3.
The signs of the coefficients of a quadratic are important