Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

x^2-2*x+1 == 4

⇒ algebra.equations.quadratic.left-square

(x-1)^2 == 4

⇒ algebra.equations.coverup.power

x-1 == 2 or x-1 == -2

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

x == 3 or x-1 == -2

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

x == 3 or x == -1