Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

(x+2)*(x+6) == 2*x*(x-3)-3

⇒ algebra.equations.linear.distr-times

x^2+8*x+12 == 2*x^2-6*x-3

⇒ algebra.equations.quadratic.move-left

-x^2+14*x+15 == 0

⇒ algebra.equations.quadratic.nice-factors

(x+1)*(x-15) == 0

⇒ algebra.equations.quadratic.product-zero

x == -1 or x == 15