Answer: -5x-8y=-5
Step-by-step explanation:
add right sides of equation and even them with result of adding right sides of equation
4x-4y-9x-4y=-2-3
-5x-8y=-5
The answer is the option A, which is: A. Equilateral triangles.
The explanation for this answer is shown below:
By definition, a tetrahedron is a solid in three dimensions that has: six sides, four vertices and four triangular faces. These faces are equilateral triangles, which means that all the sides are equal and all the interior angles measure degrees.
The tetrahedron is also called "triangular pyramid".