Answer:
Step-by-step explanation:
1.
Shirts cost $20 each and ties cost $12 each. 
<u>Expression for the cost:</u>
Correct choice is B
2.
<u>An expression that represents 40% of a number is:</u>
Correct choice is B. False
3.
t = -2, x = 3 and z = 5
- 4z + 3x − t = 
- 4*5 + 3*3 - (-2) = 
- 20 + 9 + 2 = 
- 31
Correct choice is C. 31
 
        
                    
             
        
        
        
V = -5 because you subtract 4 from both sides then divide both sides by -7 and you get -5
        
                    
             
        
        
        
You can solve this one by adding their rates, but you have to invert the numbers they give you to find the rate. Rate is measured in something per unit of time, and "per" indicates division. So the rates are: 1/3 of an hour (Sally) and 1/6 of an hour (Steve). So add the rates: 1/3 + 1/6 = 1/2. (1/3 is 2/6, and 2/6 + 1/6 = 3/6). Since their combined rate is 1/2 of a room in one hour, it takes them two hours to paint the room. 
This answer makes sense: It takes Sally three hours by herself; with Steve's help, she's faster, but not THAT much faster, because he's pretty slow. You can often spot-check word problem answers like this by giving it a common sense once-over. If we came up with four hours, that would clearly be wrong: it should take her LONGER if she's getting help.
        
                    
             
        
        
        
Answer:
2.45, -2.45
Step-by-step explanation:
Since the equation has only one term in the unknown "x", we can solve for it isolating "x" on one side of the equal sign:

Which we can round to: x = - 2.45 and x = 2.45