20 will mark supply the missing reasons to complete the proof.

In triangle  PRQ and triangle SRT

 [ANGLE]        [Given]

  [SIDE]     [Given]

  [ANGLE]      [Vertical angle are congruent]

ASA Postulate (Angle-Side-Angle): States that:

If two angles and the included side of one triangle are congruent to the corresponding parts of another triangle, then the triangles are congruent.

then, by the ASA postulates we can say that :

Corresponding parts of congruent triangles are congruent (CPCTC) means that two triangles are congruent if their corresponding sides are equal in length and their corresponding angles are equal in measure.

Then , by CPCT we have;

they can both be solutions depends on the equation

step-by-step explanation:

what is the equation? ?

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.