5[x]=45 what does x equal ... does it equal 9

Question

5[x]=45 what does x equal...does it equal 9

 

Answer 1

Actually, it kind of depends on what level of algebra you are taking, and whether you've learned about the [ ] notation yet.

 

[x] usually refers to the "greatest integer less than or equal to x" or more easily stated, x rounded down to the nearest integer.  So [x] equals 9, as shown by Ashish.  But x itself can be any real number between 9 and 10, including 9 but not including 10.

 

As an example, 9.1234 rounded down to the nearest integer is 9 and 5 time 9 is 45.  So 9.1234 would be a solution.

 

The precise way to say it is that the solution set is the set of all real numbers greater than or equal to 9 and less than 10.

 

 

 

Answer 2

Yes.

 

5[x] = 45

 

Divide both sides by 5.

 

[x] = 45/9 = 5 Ans.