7th GR. Beginning Algebra pre-work: x for which the product of [x] and x equals 39?

[Zachandthedogs]

The symbol [x] represents the greatest integer less than or equal to x. What is the value of x for which the product of [x] and x equals 39?

 

[Deleted member 4993]

The symbol [x] represents the greatest integer less than or equal to x. What is the value of x for which the product of [x] and x equals 39?

What are your thoughts?

What is a "square" number that is nearest to 39?

Now think a bit......

 

[Dr.Peterson]

What are your thoughts?

What is a "square" number that is nearest to 39?

Now think a bit......

If that hint doesn't get you moving in the right direction, you might try sketching a graph of y = x*[x], and think about where y = 39.

Once you solve this, here's a nice extension: try solving x[x] = 31. It's a little different, but has a solution!