Answer: the answer is c
Step-by-step explanation:
I believe you are expected to simplify. To do this all you do is group like terms (x, x², x³ etc.) and then simplify the coefficients.
13. 10z + 7z - 19z² - 5z² - 17z
first you can rearrange and group like terms (remember the bring the sign in front of each term with it). I would do it like this:
-19z² - 5z² +10z + 7z - 17z
Now simplify the coefficients:
-24z² + 0z
you can omit the 0z and your simplified answer is
-24z²
Main thing to remember here is that z and z² cannot be simplified together, nor can any variable that has an exponent because the exponent makes them differ.
f(3) = 1
substitute x = 3 into f(x)
f(3) = (2 × 3) - 5 = 6 - 5 = 1
0.8 times 1200 is 960, which is the number of people when the theatre is 80% full.
→ 
8 and 10 can both be divided by 2. So, 8 ÷ 2 is 4 and 10 ÷ 2 is 5.
Hope this helps :)
