In general we know perimeter is equal to sum of each side of triangle.
SO we can add all three sides to find perimeter of triangle.
SO perimeter is = x+3 + 4x - 1 + 2x - 3
= 7x -1
As perimeter is 48.
So we can write 7x - 1 = 48
7x - 1 = 48
On adding 1 on both sides.
7x- 1+ 1 = 48 +1
7x = 49
On dividing 7 on both sides.
[tex] \frac{7x}{7} = \frac{49}{7} [/tex]
[tex]x= 7[/tex]
So length of first side is = x+3 = 7+3 = 10
Length of second side = 4x - 1 = 4*7 - 1 = 27
Length of third side = 2x - 3 = 2*7 - 3 = 11
So side of triangle = 10 . 27 , 11
