Answer:
90
Step-by-step explanation:
There is two ways to attempt this problem. The first is that you could prove that angle CDE is congruent to angle DAB (of which I'm not totally sure is possible) or option two. Your second choice is to prove that Line segment DE is a flat line because line segment AB is also a flat line.
Solution:
The given equation is:

A: Taking , x=1
L H S = 9 × 1 + 49 = 9 + 49= 58
R H S : 
L H S ≠ R H S
B: Taking x=3
L H S = 9 × 3 + 49=27 + 49=76
R HS = 
L H S ≠ R H S
C: Taking x=5
L H S = 9 × 5 + 49
= 45 + 49
= 94
R H S:

L H S ≠ R H S
(D)
when , x= 8
L H S
9 × 8 + 49
= 72 + 49
= 121
R HS:

L H S ≠ R H S