Let x = time in years;
Let y = length of the sea creatures;
For both sharks, we can describe their growth with a linear equation since they grown in a constant rate. A line equation written in slope-intercept form is
[tex]y=mx+b[/tex]Where m represents the slope(or the rate of growth) and b represents the y-intercept(in our problem, the initial length).
A certain tiger shark is 55 cm long at birth and grows 2.5 cm/year, therefore, its growth can be represented by the following equation:
[tex]y_t=2.5x+55[/tex]A certain hammerhead shark is 25 cm long at birth and grows 5 cm/year, therefore, its growth can be represented by the following equation:
[tex]y_h=5x+25[/tex]The length of the sharks will be equal when the value of those functions are the same. The solution for the following equation is the corresponding time in years
[tex]\begin{gathered} y_t=y_h \\ 2.5x+55=5x+25 \\ 5x-2.5x=55-25 \\ 2.5x=30 \\ x=\frac{30}{2.5} \\ x=12 \end{gathered}[/tex]Their length will be the same after 12 years.