Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

13 == (x-3)^2

⇒ algebra.equations.coverup.power

sqrt 13 == x-3 or -sqrt 13 == x-3

⇒ algebra.equations.coverup.onevar.minus-left

3+sqrt 13 == x or -sqrt 13 == x-3

⇒ algebra.equations.coverup.onevar.minus-left

3+sqrt 13 == x or 3-sqrt 13 == x

⇒ algebra.equations.linear.flip

x == 3+sqrt 13 or 3-sqrt 13 == x

⇒ algebra.equations.linear.flip

x == 3+sqrt 13 or x == 3-sqrt 13