Q1 Perimeter = sum of all the sides
The length of the unmarked sides are 9 -8 = 1 cm and x - 3 cm
So x + x - 3 + 3 + 1 + 8 + 9 = 28
2x = 28 - 18
2x = 10
x = 5 answer
Q2
unmarked sides = x - 8 and and 5 - 2 = 3
x + x - 8 + 3 + 2 + 5 + 8 = 30
2x = 30 - 10 = 20
x = 10 answer