can you check if i did these 3 problems right or not:

-5 (a+2)
i got: -3

simplify:
5 (x+2)
i got: 3

simplify:
(y-3) (-4)
i got: 12

If you don't know what the unknowns a, x and y are, you cannot calculate a numerical value.

I think you misinterpreted the problem. Just simplify as follows:

-5 (a+2) = -5a -10
5 (x+2) = 5x + 10
etc

thats what i thought i needed to know what a x and y were? but it was on my test and i got it wrong. now i have to correct but i don't know how. heres how instruction on test are:

find the products:
-5 (a+2)

answer choices were:
a) -5a -3
b) -5a +10
c) -5a +2
d) -5a -10
i don't know which is correct

the other 2 problems were not multiple choice. just
simplify:
5(x+2)

(y-3)(-4)

find the products:

-5 (a+2)

answer choices were:
a) -5a -3
b) -5a +10
c) -5a +2
d) -5a -10
i don't know which is correct

When you multiply a negative by a positive, the product is negative.

5(x+2) = 5x + 10

(y-3)(-4) = -4y + 12

To check if you did these problems right, let's go through each one:

Problem 1:
-5(a+2)
To simplify this expression, you can distribute the -5 to both terms inside the parentheses:
-5 * a = -5a
-5 * 2 = -10
So the expression simplifies to -5a - 10.

Problem 2:
5(x+2)
Similar to the first problem, distribute the 5 to both terms inside the parentheses:
5 * x = 5x
5 * 2 = 10
So the expression simplifies to 5x + 10.

Problem 3:
(y-3)(-4)
Multiply each term inside the parentheses by -4:
-4 * y = -4y
-4 * -3 = 12
So the expression simplifies to -4y + 12.

Therefore, your answers are incorrect. The correct simplifications for the problems are:
Problem 1: -5a - 10
Problem 2: 5x + 10
Problem 3: -4y + 12.