Answer:
x=5
Step-by-step explanation:
Congruent triangles mean they have the same side lengths, so the equation here is x^2-7=4x-2. Then, solve the quadratic equation:
x^2-7=4x-2
x^2-4x-5=0
(x-5)(x+1)=0
x=5,-1
Since a side of a triangle can't be negative, the answer is 5.
