Answer:
The length of the congruent side is 3x+3y-3 units
Step-by-step explanation:
An isosceles triangle has 2 of its side equal.
The perimeter is calculated by adding the length of all the sides.
The difference between the perimeter and the base equals the sum of the two congruent sides
Thus;
(7x + 5y -8) - (x -y -2)
= 7x + 5y -8 -x + y + 2
Collect like terms
7x - x + 5y + y -8 + 2
= 6x + 6y -6
Now dividing this by 2 will give the length of the individual congruent side
(6x + 6y -6)/2 = 3x + 3y - 3
