C. Find two numbers that multiply to 11 and add to -12.

11 and -1

Step-by-step explanation:

Represent the numbers by x and y.  Then x*y = 11 and x + y = -12.

Let's eliminate y temporarily.  Solving the first equation for y yields 11/x.  Substituting this 11/x for y in the second equation yields  x + 11/x  = -12.

Let's clear out the fractions by multiplying all of these terms by x:

x^2 + 11 = -12x, or  x^2 + 12x + 11 = 0.

This factors to (x + 11)(x + 1) = 0, so the roots are -11 and -1.

Note that -11 and -1 multiply to +11 and that -11 and -1 add to -12.

answer:

step-by-step explanation:

so, converting firstly the mixed fractions to improper fractions and then "adding".