Solve the equation x squared equals 4?

Answer 1

x^2 = 4

We note that '4' = 2^2

So we write

x^2 = 2^2

You could square root both sides to x = 2 , but that is not the whole answer.

So we write

x^2 - 2^2 = 0

Remember two squared terms with a NEGATIVE between will factor. NB A POSITIVE does not factor.

X^2 - 2^2 = 0

(x - 2)(x + 2) = 0 NB Note the different signs.

x - 2 = 0

x = 2 ( as before)

&

x + 2 = 0

x = -2

So 'x' can have two values a positive and a negative; not just a positive.

This result is often written as x = +/-2 .

Answer 2

x = 2