How to solve the problem

Answer:
x=5
Step-by-step explanation:
∠D=∠E (angles opposite to equal sides are equal)
So, [tex]x^{2}[/tex]=3x+10
10=[tex]x^{2}[/tex]-3x
10=x(x-3)
we know 5×2= 10 & 5-3=2,
So, 10=5×(5-3)
10=5×2
∴x=5