Differentiate both sides wrt 
:
By the chain rule, we get
Solve for 
:
Step-by-step explanation:
from what I can see there are 2 options to make the 2 triangles congruent :
either the opposite sides must be equal or the neighboring sides must be equal.
so, either
5x = 3x + 10
and
5x - 2 = 4x + 3
or
5x = 4x + 3
and
5x - 2 = 3x + 10
for the first
5x = 3x + 10
2x = 10
x = 5
control
5x - 2 = 4w + 3
5×5 - 2 = 4×5 + 3
23 = 23
correct.
for the second
5x = 4x + 3
x = 3
control
5×3 - 2 = 3×3 + 10
15 - 2 = 9 + 10
13 = 19
no, not a valid solution.
so, x = 5
10 (13) 15
35 (37) 40
45 (48) 50
60 (61) 65
90 (93) 95
