The answer depends on what the starting expression is. It is not easy to generate an equivalent expression for trigonometric functions, for example, without using an infinite series of exponents.
A + B = B + A (commutative property)
5 x 7
86 = 2 x 43
2 x 3 x 11
Beacause with a formula you are finding out a problem. Just like evaluating means to find out or to solve.
Not sure what you mean by "zero element". If an expression is equal to zero, and you can factor it, then at least one of the factors must be zero; this is often useful to solve an equation.
With great difficulty because it is not a quadratic equation or even a quadratic expression.
You can:* Add the same expression to both sides of an equation * Subtract the same expression from both sides * Multiply the same expression (must not be zero) to both sides * Divide both sides by the same expression (must not be zero)