The two numbers are -3 and 2
Solution:
Let the two numbers be "x" and "y"
The sum of the two numbers is -1
Therefore,
x + y = -1 ------ eqn 1
Four times a number minus twice another number is -16
Therefore,
4 times x - 2 times y = -16
4x - 2y = -16 -------- eqn 2
Let us solve eqn 1 and eqn 2
From eqn 1,
x = -1 - y --------- eqn 3
Substitute eqn 3 in eqn 2
4(-1 - y) - 2y = -16
-4 - 4y - 2y = -16
-6y = -12
y = 2
Substitute y = 2 in eqn 3
x = -1 - 2
x = -3
Thus the two numbers are -3 and 2