Exercise algebra.equations.quadratic.no-abc
Description
solve a quadratic equation without abc-formula
Derivation
7*x^2+9*x == 0
⇒ algebra.equations.quadratic.common-factorx*(7*x+9) == 0
⇒ algebra.equations.quadratic.product-zerox == 0 or 7*x+9 == 0
⇒ algebra.equations.coverup.onevar.plusx == 0 or 7*x == -9
⇒ algebra.equations.coverup.timesx == 0 or x == -9/7