Answer
The photo is 8 by 12.
Work Step by Step
Note, the 5 step process is as follows:
(1) Familiarize yourself with the problem.
(2) Translate the problem into Algebra.
(3) Solve.
(4) Check. Note, if we want to check a solution, we would plug it back into the equation and check that the equation yields a true statement.
(5) State the answer.
After becoming familiar with the problem, we find:
$$w\left(w+4\right)=96 \\ w^2+4w-96=0 \\ w_{1,\:2}=\frac{-4\pm \sqrt{4^2-4\cdot \:1\left(-96\right)}}{2\cdot \:1} \\ w=8 \ \text{(Since only positive solutions count).} \\ l=8+4=12$$
The photo is 8 by 12.
