Tim solved the equation: `x+7=-15`
When he "checked back," his solution didn't work.
What was his error?
"Grade" his paper and provide helpful feedback below. You can either include the steps to get the correct answer or describe what he did wrong.
To solve the equation `x + 7 = -15`, we need to isolate the variable x by getting it alone on one side of the equation.
Here's how Tim attempted to solve the equation:
1. `x + 7 = -15` (Given equation)
2. `x = -15 - 7` (Subtracted 7 from both sides)
Now, let's evaluate the result:
3. `x = -22`
However, Tim's solution is incorrect. Let's see why:
When Tim subtracted 7 from both sides in step 2, he made an error by incorrectly performing the subtraction. The correct calculation should be -15 - 7 = -22.
Therefore, Tim's mistake was in incorrectly evaluating -15 - 7, leading to his incorrect solution of x = -22.
To solve the equation correctly, we need to subtract 7 from both sides as follows:
1. `x + 7 = -15` (Given equation)
2. `x + 7 - 7 = -15 - 7` (Subtract 7 from both sides)
3. `x = -22`
To help Tim improve his understanding and technique in solving equations, it would be helpful to explain the correct steps to him. Additionally, he should pay careful attention while performing mathematical operations, especially when dealing with negative numbers. With practice, he will be able to solve similar equations accurately.