Video Transcript
Without calculating, determine if
the square root of 121 is greater than, equal to, or less than the cube root of
negative 42.
The key to this question is we’re
asked to answer it without calculating the square root of 121 or the cube root of
negative 42. As a result, we need to recall some
key properties of square rooting and cube rooting numbers. Let’s begin by recalling what
happens when we square root positive and negative numbers. Square rooting any positive number
gives us a positive answer. When we attempt to square root a
negative number, there are no real solutions. In this question, we have the
square root of 121. And since 121 is positive, the
square root of 121 will also be positive and is therefore greater than zero.
Let’s now consider what happens
when we cube root positive and negative numbers. The cube root of any positive
number gives us a positive answer, whereas the cube root of any negative number
gives a negative answer. In this question, we have the cube
root of negative 42. This will give us a negative
answer, which is therefore less than zero.
We can therefore conclude that the
square root of 121 is greater than the cube root of negative 42, since any positive
number will be greater than any negative number. The correct answer is greater
than.
