Question

The sum of the three numbers is -4. The second number decreased by the third is equal to the first. The sum of the first and second numbers is -5. Find the numbers.
a. 2, 5, 6.
b. -2, 2, 3.
c. 6, 7, -9.
d. -3, -2, 1.

Answer 1

Do you have an idea of what it might be? I don't want to give you the answer, but I'll definitely help you find it.

Answer 2

The quickest way to solve this problem is to go through each answer choice and eliminate the wrong ones:
"The sum of the first and second numbers is -5"
Go through each answer choice and see which choice has the first and second number add up to -5.
Just to be safe make sure the other conditions given in the problem are also satisfied: "The sum of the three numbers is -4" and "The second number decreased by the third is equal to the first."

Answer 3

Without possible answers - construct system of linear equations and solve it:

a+b+c=-4
b-c=a
a+b=-5

http://www.hackmath.net/en/calculator/solving-system-of-linear-equations?input=a%2Bb%2Bc%3D-4%0D%0Ab-c%3Da%0D%0Aa%2Bb%3D-5&submit=Calculate

Result:
a = -3
b = -2
c = 1

do D is good