Final answer:
To solve for the value of the variable a and MN, substitute the given values into the equations and solve for a. Then substitute the value of a back into the equation MN = 10a.
Step-by-step explanation:
To solve for the value of the variable and MN, we can set up the following equations:
LM = 5a
LN = 30
MN = 10a
We can substitute the value of LM and LN into the equation MN = 10a:
5a = 30 - LN
Solving for a:
a = (30 - LN) / 5
Now, we can substitute the value of a back into the equation MN = 10a:
MN = 10((30 - LN) / 5)
For example, if LN = 20, then a = (30 - 20) / 5 = 2. MN would be 10 * 2 = 20.