In parallelogram mnop , pk=5x and kn=x2−14 . what is pn ? 7 36 70 100

PK=5x and KN=x2−14 
PK = KN
so
5x = x^2 - 14
x^2 - 5x - 14 = 0
(x -7)(x+2) = 0
x+2=0,x = -2
x-7=0;x = 7
so answer for x is 7
PK=5x  = 5(7) = 35
KN=x^2−14 = 7^2 - 14 = 49 - 14 = 35
and 
PN = PK + KN
PN = 35 + 35
PN = 70

answer
C. 70

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!