How do you find tan (-7 pi/2) without using a calculator and what would the answer be?

Step-by-step explanation:

tan (-7 π/2)=-tan (7π/2)=-tan ( 2π+3π/2)=-tan (3π/2)=-tan (π+π/2)=-tan (π/2)=-∞

An art school orders 20 charcoal pencils for each student in a portrait class and 26 extra pencils in case more are needed.

Let s represent the number of students in the class and c represent the total number of charcoal pencils the school orders.

Find the value of c when s=4.

c=

Step-by-step explanation: