An triangle is also an acute and equilateral triangle.

Equiangular

Right

Isoceles

Right

Step-by-step explanation:

A right triangle has acute angles and is an equilateral triangle.

Equiangular Triangle

The angles A,B and C always remain equal in measure. The sides of an equiangular triangle are all the same length (congruent), and so an equiangular triangle is really the same thing as an equilateral triangle.

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.