What type of triangle can an equilateral be?

An acute triangle.

Step-by-step explanation:

There is a rule that if a triangle is equilateral, then it also must be acute. A right and obtuse triangle will always have a scenario where one of the sides is longer both of the other sides. And, if the triangle has at least one side longer than the other, it cannot be a equilateral triangle. Therefore, an equilateral triangle can also be an acute triangle. Hope this helps!

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form