The sides have x in them? Leave it in
Solve a right triangle whose sides are expressions without the quadratic, then a sine-equals-cosine equation in degree mode.
1:41 · Right Triangles and Trigonometry
Worked in this video
In right triangle ABC, the right angle is at C. Leg AC has length x, leg BC has length x + 7, and the hypotenuse AB has length x + 8.
What is tan A?
On paper that is expanding two squares, collecting terms, factoring a quadratic and throwing away the negative root — five steps before the trig even starts. In Desmos, type the Pythagorean equation with the x left in: x² + (x + 7)² = (x + 8)². Desmos solves it and draws the answer as a line at x = 5, so the legs are 5 and 12 and the hypotenuse is 13. Tangent of A is opposite over adjacent: 12/5.
Answer: tan A = 12/5