Answer:
JM = 7
Step-by-step explanation:
Triangles LMN and LJK are similar, so corresponding sides have teh same ratio:
LM/MN = LJ/JK
14/(JM+3) = (14 +JM)/15
210 = (JM +3)(JM +14) . . . . . multiply by 15(JM +3)
JM² +17JM -168 = 0 . . . . . . . subtract 210; put in standard form
(JM +24)(JM -7) = 0 . . . . . . factor
The values for JM that make this true are 7 and -24. The length must be positive, so ...
JM = 7
