Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

56 == 12*(x^2-3*x)+8

⇒ algebra.equations.coverup.onevar.plus

48 == 12*(x^2-3*x)

⇒ algebra.equations.coverup.times

4 == x^2-3*x

⇒ algebra.equations.linear.flip

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