Help me solve this pleaseee

Answer:
Solution given:
perimeter of rectangle: 2(l+b)=2(3x-3+x-3)
perimeter of triangle: sum of all side
= 2x-1+2x-1+2x=6x-2
Since both perimeter are equal
8x-12=6x-2
8x-6x=12-2
2x=10
x=10/2
x=5