Evaluate Squares

What does it mean to be squared? Start with visualizing a square □ . We know that the length and width of a square are the same length and we know that the area of a square is side times side. We can write this as s2. So any time you see a number or a variable with an exponent of 2 it means you are multiplying a number times itself.

x2=x •x •x


Let's practice with numbers.

Example 1: 52 = 5 •5 = 25

Example 2: 122 = 12 •12 = 144

Let's practice evaluating with variables.

Example 3: if x = 6 find x2.

Substitute (6) in for x.
x2 = (6)2


Expand
x2 = 6 •6 = 36


Therefore
x2 = 36


Let's look at a common mistake.

Remember that x2 = x •x so what does -x2 mean? It means (-1) •x •x

Example 4: find when x = 7

Substitute (7) in for x.
x2 = (7)2
Expand
x2 = 7 •7 = 49
Therefore
x2 = 49


Challenge: find 2x2 when x = 9

Substitute (9) in for x.
2x2 = 2(9)2
Expand
2x2 = 2 •9 •9 = 162
Therefore
2x2 = 162


Let's wrap this up. Remember that to be "squared" means to multiply a number times itself.

Related Links:
Math
algebra
Evaluate Exponents


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