Exercise algebra.equations.quadratic.no-abc

Description
solve a quadratic equation without abc-formula

Derivation

2*(x+4) == (x-7/2)^2
algebra.equations.quadratic.distr-square
2*(x+4) == x^2-7*x+49/4
algebra.equations.linear.distr-times
2*x+8 == x^2-7*x+49/4
algebra.equations.quadratic.move-left
-x^2+9*x-17/4 == 0
algebra.equations.quadratic.scale
x^2-9*x+17/4 == 0
algebra.equations.quadratic.prepare-split
x^2-9*x+81/4 == 16
algebra.equations.quadratic.left-square
(x-9/2)^2 == 16
algebra.equations.coverup.power
x-9/2 == 4 or x-9/2 == -4
algebra.equations.coverup.onevar.minus-left
x == 17/2 or x-9/2 == -4
algebra.equations.coverup.onevar.minus-left
x == 17/2 or x == 1/2