I don't understand plz help

Answer:
The equation that represent x, the height of the sign is;
[tex]2a = 3x[/tex]
Step-by-step explanation:
Given that the area of the triangular yield is A square feet
and it has a base length of 3 feet.
also the height is represented by x;
[tex]b = 3ft \\ h = x[/tex]
Recall that the area of a triangle can be written as;
[tex]a = \frac{1}{2} bh[/tex]
substituting the given;
[tex]a = \frac{1}{2} \times 3 \times x \\ a = \frac{3}{2} x \\ 2a = 3x[/tex]
Therefore, the equation that represent x, the height of the sign is;
[tex]2a = 3x[/tex]