What is the perimeter of the shaded triangle

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

What would be the reasons for lines 3 and 4? a. addition property; subtraction property b. addition property; solve c. substitution property; subtraction property d. substitution property; prove

Aline has a slope of negative 1/4 the past two points -5/4 and 1 what is the equation of the line