GUIDE深度 · Deep dive
Quadratics and Systems
For a quadratic, try factoring: find two numbers that add to b and multiply to c in x²+bx+c=0. For systems, eliminate one variable by adding/subtracting the equations, then substitute back.
Quadratics
(x-r1)(x-r2)=0 -> x=r1 or r2.
Do not drop negative roots.
Systems
Eliminate, solve one variable.
Substitute back for the other, then write the pair.
FAQ
Negative discriminant?
No real roots; this deck only uses factorable cases.
Is a system always unique?
No; parallel means none, coincident means infinitely many.