Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

-2*x*(2*x+10) == 4*(10-x^2)

⇒ algebra.equations.quadratic.same-con-factor

-x*(2*x+10) == 2*(10-x^2)

⇒ algebra.equations.linear.distr-times

-2*x^2-10*x == 20-2*x^2

⇒ algebra.equations.quadratic.cancel

-10*x == 20

⇒ algebra.equations.coverup.times

x == -2