Since K is between points J and L. We can conclude:
JK + KL = JL
Where:
JK = x² - 4x
KL = 3x - 2
JL = 28
Replacing the values:
x² - 4x + 3x -2 = 28
Solving for x:
Subtract 28 from both sides:
x² - 4x + 3x - 2 - 28 = 28 - 28
x² - 4x + 3x - 30 = 0
x² - x - 30 = 0
Factor:
(x - 6)(x + 5) = 0
x = 6 or x = -5
since a negative length wouldn't make any sense:
x = 6
Replace the value of x into JK and KL:
JK = x² - 4x = 6² - 4(6) = 36 - 24 = 12
KL = 3x - 2 = 3(6) - 2 = 18 - 2 = 16