Which operation should be performed first to simplify the expression below? 19 - 2 \times 8 \div 4 + 6

A
Addition
B
Subtraction
C
Multiplication
D
Division

The zoo collects $9.60 for every 24 tickets sold. how much will be collected for 400 tickets?

I’ve been trying all day to figure this puzzle out. i need the work for it aswell. it is a factoring polynomials tarsia. the image is below.

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.)