Answer: False
Explanation:
Definition of equilateral triangle :- A triangle having all sides equal is known as equilateral triangle.
Definition of isosceles triangle :- A triangle having any two sides equal is known as isosceles triangle.
By the above definition is is clear that if a triangle is equilateral triangle then it will satisfy the definition of isosceles triangle too.
Therefore, the statement "some equilateral triangles are not isosceles" is false.