Answer:
Option 4: y -x
Explanation:
Option 1
Multiplying a positive and a negative number will result in a negative number.
For example, if x= -1 and y=5,
x(y)= -1(5)= -5 (a negative number)
Thus, option 1 is incorrect.
Option 2
In this option, we are essentially multiplying -1 to y, a positive number, before adding the result with x.
Since y is a positive number, -y is a negative number and hence x -y (when x is a negative number) will result in a negative number. Let's plug in values into x and y to check this.
For example, x= -2 and y=3.
x -y= -2 -3= -5
Option 2 is thus incorrect.
Option 3
Dividing a positive number with a negative number will result in a negative number.
For example: 6÷(-2)= -3
Option 3 is also incorrect.
Option 4
Subtracting a negative number from a positive number will result in a positive number.
For example: x= -1, y= 8
y -x= 8 -(-1)= 8 +1= 9
As seen from the example above, when the negative number is multiplied to negative 1, a positive sign results.
In summary, when a positive number is multiplied to a positive number, the resulting number is positive.
When a negative number is multiplied to a negative number, the resulting number is positive.
When a positive number is multiplied to a negative number, the resulting number is negative.
+(+)= +
-(-)= +
+(-)= -
This applies to division too.