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Given: E is the midpoint of segment DF

DE = 8x
EF = 63 - x
Prove: x = 7
Use a 2-column proof.

User Velidan
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1 Answer

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Final answer:

To prove that x = 7, we need to show that DE is equal to 8 times EF. Given that E is the midpoint of segment DF, we can use the midpoint formula to find the coordinates of E. From there, we can set up equations using the given information DE = 8x and EF = 63 - x. By simplifying the equations and setting DE equal to EF, we can find the value of x to be 9, not 7.

Step-by-step explanation:

To prove that x = 7, we need to show that DE is equal to 8 times EF. Given that E is the midpoint of segment DF, we can use the midpoint formula to find the coordinates of E. Let's assume that D has coordinates (a, b) and F has coordinates (c, d). The midpoint formula states that the coordinates of the midpoint E are [(a + c)/2, (b + d)/2]. Since E is the midpoint, we can set [(a + c)/2, (b + d)/2] = E. From here, we can set up equations using the given information DE = 8x and EF = 63 - x.

1. DE = 8x

2. EF = 63 - x

Substitute the coordinates of E into the equations:

1. [ (a + c)/2, (b + d)/2] = 8x

2. (b + d)/2 = 63 - x

From the first equation, we can see that (a + c)/2 = 8x and (b + d)/2 = 63 - x. Simplify the equations.

3. a + c = 16x

4. b + d = 126 - 2x

Since E is the midpoint, DE and EF are equal in length. Set up an equation using this information:

5. DE = EF

6. 8x = 63 - x

Now solve equation 6 for x:

7x = 63

x = 63/7

x = 9

Therefore, x = 9 and not x = 7. Please check the given information and restate the problem if needed.

User MarGa
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