Classify triangles by distance formula

Is the triangle with vertices (-9, 3) and (7, 9) and (-7, 1) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (7, 6) and (3, -9) and (8, -9) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (7, 1) and (1, 7) and (10, -1) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (-4, -9) and (-7, 0) and (5, -5) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (-7, 7) and (7, 4) and (-5, 7) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (-7, 9) and (-7, 10) and (-1, -9) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (7, 3) and (-7, 11) and (5, 19) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (5, 9) and (1, 26) and (21, 16) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (1, 4) and (-16, 11) and (14, 17) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene

Is the triangle with vertices (-5, -5) and (8, -19) and (-7, -24) equilateral, isosceles or scalene?

• equilateral
• isosceles
• scalene