I'm assuming your teacher wants you to distribute. If so, then you multiply the outer term 8 by each term inside (3a and 5). After that you add.
8 times 3a = 24a
8 times 5 = 40
So 8(3a+5) becomes 24a+40
We do not combine 24a and 40 as they are not like terms. So we leave 24a+40 as it is.
 
        
                    
             
        
        
        
Answer:
She didn't put the sign's in the proper place, it should be ( x + 3 ) ( x - 7 )
Step-by-step explanation:
( x - 3 ) ( x + 7 ) = x² + 7x - 3x - 21 = x² + 4x - 21
( x + 3 ) ( x - 7 ) = x² - 7x + 3x - 21 = x² - 4x - 21
 
        
                    
             
        
        
        
I am pretty sure it’s false
        
                    
             
        
        
        
10) 1 gallon of water for every inch of the fish's body length.
a) 2 1/2 inches long fish needs 2 1/2 gallon of water.
b) tank: l = 7 inches ; w = 5 inches; h = 7 ; volume = 7in * 5in * 7in = 245 in³
c) no. her fish tank is not large enough for the fish.
volume of 1 gallon of water is 231 in³, water needed is 2 1/2 gallon, so 5/2 * 231 in³ = 577.50 in³ volume.
11) volume = 7in * 3.5in * 1.75 in = 42.875 in³ 
weight of the brick = 0.1 pound per cubic inch ⇒ 42.875 in³ * 0.1 lb = 4.2875 pounds
weight of the gold bar = 0.7 pound per cubic inch ⇒ 42.875 in³ * 0.7 lb = 30.0125 pounds
12) l = 55cm ; w = 40cm ; h = 30 cm
volume = 55cm * 40cm * 30cm = 66,000 cm³
        
             
        
        
        
Answer:
You got this
Step-by-step explanation:
you do need lots of help but not from me so bye now :)