Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

x^2-5*x == 8*x^2+4*x

⇒ algebra.equations.quadratic.move-left

-7*x^2-9*x == 0

⇒ algebra.equations.quadratic.common-factor

-x*(7*x+9) == 0

⇒ algebra.equations.quadratic.product-zero

x == 0 or 7*x+9 == 0

⇒ algebra.equations.coverup.onevar.plus

x == 0 or 7*x == -9

⇒ algebra.equations.coverup.times

x == 0 or x == -9/7