Whats the constant of 18z-7(-3+2z)

Rob spent 25%, percent more time on his research project than he had planned. he spent an extra h hours on the project. which of the following expressions could represent the number of hours rob actually spent on the project? two answers

How many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.) how many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.)

What is the following sum in simplest form? square root 8 + 3 square root 2 + square root 32