On a math test a student, Sarah , has to identify all the coefficients and constants of the expression 9 b + 4 + y. Sarah says that 9 is a coefficient and 4 is a constant. Identify all the coefficients and constants of the expression. What error might Sarah have made?

Step-by-step explanation:

4 + n + 7m

constants are just the numbers with no variables (letters)

so the constant is 4

coefficients are numbers multiplied by variables (letters)

so the coefficients are : 7 and 1

the error sarah made is forgetting the coefficient of n ... because even if it is not written, n is the same as 1n ... so basically, there is a coefficient for EVERY variable, even if its not written.