Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

x^2-2*x == 3
algebra.equations.quadratic.move-left
x^2-2*x-3 == 0
algebra.equations.quadratic.nice-factors
(x+1)*(x-3) == 0
algebra.equations.quadratic.product-zero
x == -1 or x == 3