Under which operations is the set of whole numbers {0,1,2,} closed

Checking with Addition:

Let x, y be two whole numbers.

Then, x + y is definitely a whole number.

So, the set of whole numbers is closed under addition.

Checking with Subtraction:

Let x, y be two whole numbers.

Then, x - y may or may not be a whole number.

For example, if we take 3 and 2,

3 - 2 = 1 is a whole number but if we take 2 and 5, then

2 - 5 = -3 is not a whole number.

So, the set of whole numbers is not closed under subtraction.

Checking with Multiplication:

Let x, y be two whole numbers.

Then, x × y is definitely a whole number.

So, the set of whole numbers is closed under multiplication.

Checking with Division:

Let x, y be two whole numbers.

Then, x / y may or may not be a whole number.

For example, if we take 6 and 3,

6/3 = 2 is a whole number.

But, if we take 4 and 5,

4/5 is not a whole number.

So, the set of whole numbers is not closed under division.

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15