Answer: -2
Step-by-step explanation: Let the unknown number be " a"
From the statement,
a^2 - 12 = 4a ..... this is a quadratic equation
i.e a^2 - 4a - 12 = 0
factorizing the quadratic expression
( a + 2 ) ( a - 6 ) = 0
i.e a = -2 or 6
so, the negative solution is -2
