(-18) \ (-2) -15
To solve this expression, we can use the order of operations, which states that we should perform the operations inside parentheses first, then do any multiplication or division from left to right, and finally perform any addition or subtraction from left to right.
In this expression, we don't have any parentheses, so we can move on to performing the division. To divide two numbers, we can multiply the first number by the reciprocal of the second number.
Reciprocal of -2 is -1/2. Therefore, (-18) ÷ (-2) is the same as (-18) × (-1/2).
Using the rule of multiplying a negative number by a positive number gives a negative product, we can calculate (-18) × (-1/2) as:
= -18 × (-1/2)
= 18/1 × 1/2 (We can write -1 as 1/1)
= 18/2
= 9
Finally, we subtract 15 from 9:
9 - 15 = -6
So, (-18) ÷ (-2) - 15 equals -6.