Step-by-step explanation: In the given figure M is a midpoint .By definition of midpoint AM=MD.It is given AB=CD in figure. Two of the sides are equal .to prove the triangles to be congruent by SSS the third side must be equal
That is BM=CM,
Or 4x-1=3x+6
Subtracting 3x both sides
4x-3x-1=3x-3x+6
x-1=6.
Adding 1 both sides
x=7.
x=7 will make the third side equal and hence the triangles will be congruent by SSS.
