Question 4651
Let the two numbers be x and y:

Then:
x - y = 11  Rewrite this as:  x = 11 + y and substitute into the 2nd equation.
xy = 42

(11 + y)y = 42  Simplify.
y^2 + 11y - 42 = 0  Solve by factoring.

(y + 14)(y - 3) = 0  Apply the zero products principle.

y - 3 = 0; y = 3  or
y + 14 = 0; y = -14  

x = 11 + y
x = 11 + 3 = 14  or
x = 11 + (-14) = -3

The numbers are:  14 and 3 or -3 and -14

Check:
  14-3 = 11 and 14(3) = 42 or
-3-(-14) = 11 and (-3)(-14) = 42