When you add a zero to the problem, it shows you are now multiplying in the double-digits. Let's say you are multiplying 12x12. First you cover up the one then multiply them. Then cover up the two and you have 10. When you multiply them, it ends in a zero. Don't think of it as adding a zero but adding to products.
-4 I believe I’m not sure tho
30-(11+(18-(48/8×2))+7)+15
= 30-(11+(18-12)+7)+15
= 30-(11+6+7)+15
= 30-24+15
= 21
20/2.5 = 8
So 8 movies can be shown in 20 hours.
Expand
simplify 36 - 4.5x + 36 to -4.5x + 72
simplify 102 - 7.5x - 60 to -7.5x + 42
add 7.5x to both sides
simplify -4.5x + 72 + 7.5x to 3x + 72
subtract 72 from both sides
simplify 42 - 72 to -30
divide both sides by 3
simplify 30/3 to 10
Answer: x = -10
