Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

8*x^2+4*x-24 == (x+3)*(x-8)

⇒ algebra.equations.linear.distr-times

8*x^2+4*x-24 == x^2-5*x-24

⇒ algebra.equations.quadratic.cancel

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