Verify the Rational Expression: Is (-x+7)/(x-7) = 1 Correct?

Question

Determine if the simplification below is correct:

x+7x7=1 \frac{-x+7}{x-7}=1

Video Solution

Solution Steps

00:00 Determine if the reduction is correct
00:03 Take out the minus from the parentheses
00:14 Reduce what we can, when reducing the entire fraction there's always 1 remaining
00:19 In this case (-1) will remain due to the minus we took out from the parentheses
00:23 Compare between the expressions
00:31 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Simplify the equation x+7=x7-x + 7 = x - 7.
  • Step 2: Solve for xx to verify if the equation holds true.

Now, let's work through each step:
Step 1: Starting with the equation x+7=x7-x + 7 = x - 7, we'll simplify by adding xx to both sides:
x+7+x=x7+x-x + 7 + x = x - 7 + x
This simplifies to 7=2x77 = 2x - 7.
Next, add 7 to both sides to further simplify:
7+7=2x7+77 + 7 = 2x - 7 + 7
This gives 14=2x14 = 2x.
Step 2: Divide both sides by 2 to solve for xx:
x=142x = \frac{14}{2}
Thus, x=7x = 7.

However, substituting x=7x = 7 into the original expression x+7x7\frac{-x + 7}{x - 7} results in division by zero, which is undefined. Therefore, x+7-x + 7 cannot be equal to x7x - 7 for all values of xx, and the simplification of the expression to 1 is incorrect under normal mathematical rules.

The simplification provided in the problem is incorrect.

Answer

Incorrect