-7
15-X
(56/8) -8
NO
8 + x 40 is not a valid mathematical expression.
8+(7x9)
It is: 7*(8*15) = 840
The expression for 7 less than 15 is written as (15 - 7). When you calculate this, it equals 8. Therefore, 7 less than 15 can be expressed as (15 - 7 = 8).
It is: 8+7 = 15
It is a more complicated mathematical expression.
When evaluating the expression ( 15 - 5(15 - 7) ), you should first address the parentheses. Calculate ( 15 - 7 ) to get ( 8 ). Then, substitute back into the expression, resulting in ( 15 - 5 \times 8 ). Finally, perform the multiplication before the subtraction.
Yes, a mathematical expression can have no variables, but such an expression is usually not very useful. An example of a valid expression without variables is: 1+1=2
The expression "8 8n n 2" seems to be unclear or incorrectly formatted. If you meant to express a mathematical operation involving variables and numbers, please clarify the intended operation (e.g., multiplication, addition) and the arrangement of the terms. As it stands, it does not represent a standard mathematical expression.