Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

x^2-2*x+1 == 1
algebra.equations.quadratic.left-square
(x-1)^2 == 1
algebra.equations.coverup.power
x-1 == 1 or x-1 == -1
algebra.equations.coverup.onevar.minus-left
x == 2 or x-1 == -1
algebra.equations.coverup.onevar.minus-left
x == 2 or x == 0