What does tis mean?

Question

I've got these types of questions on my computer test:

ex.: 4x​( 4-1)

What does this mean. Can you explain? Thanks!

Answer 1

Pemdas

parentheses

Exponents

multiplication & division

addition & subtraction

 

the stuff in parentheses you calculate first

 

E.g.: 4 x (4-1) = 4 × 3(cuz 4-1=3) =12

Hope this helps

Answer 2

 

(2x^2 + 1)(2x^2 - 1) 

Sorry I have a hard time to explain this

Answer 3

nope sorry..i dont realy know what it means i just wanna answer for no aparent reason