The value of x is 13.
An equilateral triangle has all its three sides equal.
The Perimeter of an equilateral triangle with length L is given as:
P = 3L
Here in this question, we are given that the perimeter, P is 48, and the length, L is x + 3.
We can use this information to find the value of x.
That is, simply,
48 = 3(x + 3)
Expanding the bracket on the right hand side and collecting like terms would help us obtain the value of x.
Doing this, we have:
48 = 3x + 9
Subtract 9 from both sides
48 - 9 = 3x
39 = 3x
Divide both sides by 3
39/3 = x
x = 13
Therefore, the value of x is 13