Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

0 == x^2-9*x+18

⇒ algebra.equations.linear.flip

x^2-9*x+18 == 0

⇒ algebra.equations.quadratic.nice-factors

(x-3)*(x-6) == 0

⇒ algebra.equations.quadratic.product-zero

x == 3 or x == 6