Answer:
x = 5
Explanation:
The ≅ sign means that both triangles are congruent, also meaning they're exactly the same. So with this in mind, the equations naturally equal each other:
3x + 3 = 5x - 7
Subtract 5x from both sides
-2x + 3 = -7
Subtract -3 from both sides
-2x = -10
divide by -2 to both sides
x = 5