Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

(x-4)*(x-1) == 11

⇒ algebra.equations.linear.distr-times

x^2-5*x+4 == 11

⇒ algebra.equations.quadratic.move-left

x^2-5*x-7 == 0

⇒ algebra.equations.quadratic.prepare-split

x^2-5*x+25/4 == 53/4

⇒ algebra.equations.quadratic.left-square

(x-5/2)^2 == 53/4

⇒ algebra.equations.coverup.power

x-5/2 == sqrt (53/4) or x-5/2 == -sqrt (53/4)

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

x == 5/2+sqrt (53/4) or x-5/2 == -sqrt (53/4)

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

x == 5/2+sqrt (53/4) or x == 5/2-sqrt (53/4)

⇒ algebra.equations.quadratic.simpler-sqrt

x == 5/2+1/2*sqrt 53 or x == 5/2-1/2*sqrt 53