Answer: -2
Step-by-step explanation: When your adding and subtracting positives and negatives, it helps to use a number line to visualise what's going on in the problem.
On a number line zero is in the middle. All numbers to the right of zero are positive and all numbers to the left of zero are negative.
So when your simplifying a problem like 3 + (-5), we start at zero and positive 3 takes us to the right. From there, -5 moves us 5 units back to the left and we end up -2. So 3 + (-5) simplifies to -2.
I have attached a number line along with my work
for this problem below.