The given problem can be exemplified in the following diagram:
Since we are told that "P" is a mid-point of DE, this means that:
![DP=PE](https://img.qammunity.org/2023/formulas/mathematics/college/jxqn9wdpdgkp4hd3o1287ggotnmmeig32v.png)
Also, since DE represents the entire segment, this means:
![DP+PE=DE](https://img.qammunity.org/2023/formulas/mathematics/college/vc5zf6c655brjho9v7cfvfqdmecxjxc3gz.png)
Therefore, we may replace the values of DP and PE as "6x + 4" and we also replace the given values of DE, we get:
![(6x+4)+(6x+4)=14x-10](https://img.qammunity.org/2023/formulas/mathematics/college/70eji2z0wvdnsnxznsg3jcbqjtt5ct8xl9.png)
Adding like terms we get:
![12x+8=14x-10](https://img.qammunity.org/2023/formulas/mathematics/college/ape2wtnkfx84xyf11xvs84oph822b4cvdt.png)
Now we solve for "x" first by subtracting 14x from both sides:
![\begin{gathered} 12x-14x+8=14x-14x-10 \\ -2x+8=-10 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/a8piqpxi0744w4rl36u1w6ehlfh1cm6e3u.png)
Now we subtract 8 from both sides:
![\begin{gathered} -2x+8-8=-10-8 \\ -2x=-18 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/48qzxff66y7e3x33s5ql86bc1qedf99f1t.png)
Now we divide both sides by -2:
![x=-(18)/(-2)=9](https://img.qammunity.org/2023/formulas/mathematics/college/m48jcybm8tl9hdm62fd0mwly8f0jzm7drn.png)
Therefore, the value of "x" is 9. Now we determine the length of DP using the expression for this segment:
![DP=6x+4](https://img.qammunity.org/2023/formulas/mathematics/college/ciqcfuymc2j5vv713m5ujwclyq3dfvu0mt.png)
Replacing the value of "x":
![DP=6(9)+4](https://img.qammunity.org/2023/formulas/mathematics/college/jmpv6mg03j66tp0wjnnea66pzpoj3h7utx.png)
Solving the operations we get:
![DP=58](https://img.qammunity.org/2023/formulas/mathematics/college/ylg1f6n34w1qolpj8ueqmjs1skwrvqo1je.png)
Therefore, the length of DP is 58 units.