Always find the difference in prices first. 
<span>3.45 - 3.20 = $.25 difference </span>
<span>Always divide the difference by the original price. Change this number into a per cent. </span>
<span>.25/3.45 = .07246 = 7.2% decrease </span>
        
                    
             
        
        
        
Answer:
B.) 18
Step-by-step explanation:
To find the correct b value we use this formula
b² - 4ac = 0
b = What we are solving for
a = 1
c = 81
b² - 4(1)(81) = 0
b² - 324 = 0
b² = 324

b = ±18
And 18 is one of the answer choices 
So B.) 18 is the correct answer.
 
        
                    
             
        
        
        
12. Divide total weight by weight of each. 1200 / 1.2 = 1000.
13. Total gas divided by number of cars will give amount of gas per car. 1350 /         100 = 13.5
14. The recipe gives the amount for 10 large bags. In other words, there is 750.2 grams in 10 bags. So divide by 10 to get the amount in 1 bag, which is B
15. Do the same process from 14. for oats and sunflowers, and then add them together. Answer is A
16. This is a bit diffrent but similar idea. Recipie gives for 100 snack sizes. So if we divided sunflower by tht we get 4.505. We need 2 bags however for a total of 9.01 grams. which is D
        
             
        
        
        
put values 
Do like you do algebraic addition
- -5i+10j-24i+32j
- -5i-24i+10j+32j
- -29i+42j
Option A
 
        
             
        
        
        
Y=mx+b is slope intercept form... 
m=slope
b=y-intercept
Answer- y=-9+5