Algebra Definition

Definition: A branch of mathematics that substitutes letters for numbers. An algebraic equation represents a scale, what is done on one side of the scale with a number is also done to the other side of the scale. The numbers are the constants. Algebra can include real numbers, complex numbers, matrices, vectors etc. Moving from Arithmetic to Algebra will look something like this: Arithmetic: 3 + 4 = 3 + 4 in Algebra it would look like: x + y = y + x 

Source: http://math.about.com/cs/algebra/g/algebradef.htm

Power (Mathematics)

In mathematics, that which is represented by an exponent or index, denoted by a superior numeral. A number or symbol raised to the power of 2 – that is, multiplied by itself – is said to be squared (for example, 3², x²), and when raised to the power of 3, it is said to be cubed (for example, 2³, y³). Any number to the power zero always equals 1.

Powers can be negative. Negative powers produce fractions, with the numerator as one, as a number is divided by itself, rather than being multiplied by itself, so for example 2^-1 = 1/2 and 3^-3 = 1/27.

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