Subtract 4x from both sides
4x +2 = 7x - 13 would then simplify to
3x - 13 = 2 ( you can switch the problem around as long as you dont switch the variables around )
then you have to + 13 which simplifies to
3x = 15
then you divide by 3 which equals
x=5
A tetrahedron is also called a regular triangular pyramid.
option b is the correct answer.
The answer is 1350mm squared. Hope it helps!