Question

The sum of two numbers is -18. If the first number is 10, which equation represents this situation, and what is the second number?

A.
The equation that represents this situation is 10 − x = -18. The second number is 28.
B.
The equation that represents this situation is 10 + x = -18. The second number is -28.
C.
The equation that represents this situation is x − 10 = -18. The second number is -8.
D.
The equation that represents this situation is -10 + x = -18. The second number is -8.

Answer 1

The equation that represents this situation is 10 + x = -18. The second number is -28.

Explanation:

The sum of two numbers is -18 and the first number is 10:

As an equation it would look like this:

10 + x = -18

To find the second number, we need to isolate it on one side of the equation, while keeping the expression true.

So first we subtract 10 from both sides:

10 -10 + x = -18 - 10

x = -28

Let's check!

10 + - 28 = -18

-18 = - 18