Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

x*(x-3) == 4
algebra.equations.linear.distr-times
x^2-3*x == 4
algebra.equations.quadratic.move-left
x^2-3*x-4 == 0
algebra.equations.quadratic.nice-factors
(x+1)*(x-4) == 0
algebra.equations.quadratic.product-zero
x == -1 or x == 4