If DF = 9x -39 find EF

|DF| = |DE| + |EF|
|DF| = 9x -36
|DE| = 47
|EF| = 3x+10
Substitute:
9x - 39 = 47 + 3x + 10
9x - 39 = 3x + 57 |+39
9x = 3x + 96 |-3x
6x = 96 |:6
x = 16
Put the value of x to the equation |EF| = 3x + 10
|EF| = (3)(16) + 10 = 48 + 10 = 58
Answer: |EF| = 58
Answer: The required length of EF is 58 units.
Step-by-step explanation: Given that DF = 9x - 39, DE = 47 units and EF = 3x + 10.
We are to find the length of EF.
We have
[tex]DE+EF=DF\\\\\Rightarrow 47+(3x+10)=9x-39\\\\\Rightarrow 3x+57=9x-39\\\\\Rightarrow 9x-3x=57+39\\\\\Rightarrow 6x=96\\\\\Rightarrow x=\dfrac{96}{6}\\\\\Rightarrow x=16.[/tex]
Therefore, the length of EF is given by
[tex]EF=3\imes16+10=48+10=58.[/tex]
Thus, the required length of EF is 58 units.