Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

2*x*(2*x+10)-4*x^2+40 == 0

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

x*(2*x+10)-2*x^2+20 == 0

⇒ algebra.equations.linear.distr-times

2*x^2+10*x-2*x^2+20 == 0

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

x^2+5*x-x^2+10 == 0

⇒ algebra.equations.linear.merge

5*x+10 == 0

⇒ algebra.equations.coverup.onevar.plus

5*x == -10

⇒ algebra.equations.coverup.times

x == -2