Final answer:
The correct equation representing the situation where the sum of two numbers is -18 and one number is 10 is 10 + x = -18. Following the rules for addition with opposite signs, the second number is found to be -28. Therefore, the answer is B.
Step-by-step explanation:
The student wants to know the equation that represents the situation where the sum of two numbers is -18 and one of the numbers is 10, as well as the second number in this pair. The correct equation to represent this situation is 10 + x = -18, where 'x' is the second number. We follow the rule that when two numbers with opposite signs are added, we subtract the smaller number from the larger one and the result takes the sign of the larger number. Here, the number 10 is positive and the sum is negative, so the second number must be negative and larger in magnitude than 10 to achieve the sum of -18.
To find the value of 'x', we rearrange the equation:
- 10 + x = -18
- x = -18 - 10
- x = -28
Therefore, the correct answer is B: The equation is 10 + x = -18 and the second number is -28.