Answer: A, B and D are true statements.
Explanation:
The sum of the angles in a triangle is 180 degrees. It means that
7x + 2 + 8x + 4x + 7 = 180
Collecting like terms, it becomes
7x + 8x +4x + 2 + 7 = 180
19x + 9 = 180
Subtracting 9 from both sides of the equation, it becomes
19x + 9 - 9 = 180 - 9
19x = 171
Dividing both sides of the equation by 19, it becomes
19x/19 = 171/19
x = 9
Angle J = 7 × 9 + 2 = 65 degrees
Angle K = 8x = 8 × 9 = 72 degrees
Angle L = 4x + 7 = 4 × 9 + 7 = 43 degrees
Therefore, A, B and D are true statements.