<span>a. find the number of units of tacos she must sell to minimise her cost.
</span>to find a minimum we need to find the function derivative and make it equal to zero:
dc/dx = 2x - 40 = 0
2x = 40
x = 20
therefore to minimize the cost, she needs to sell 20 units of tacos
<span>b. find the minimum cost.
</span>that can be done by substituting the previous result, 20 tacos, in the original equation:
<span>C(x) = x^2 - 40x + 610
</span>C(20) = (20)^2 - 40(20) + <span>610
</span>= 400 - 800 + 610
= 210
the minimum cost will be 210 dollars
        
             
        
        
        
We need to multiply the factors (x - 2) and (x^2 + 9x + 10) to see if the product is the original expression given. 
(x - 2)(x^2 + 9x + 10)
x^3 + 9x^2 + 10x - 2x^2 - 18x - 20
x^3 + 7x^2 - 8x - 20.
Since the product just found is not the original expression given, Jimmy is wrong.
I will complete the work on paper by synthetic division and post my answer. 
After using synthetic division, the correct quotient is x^2 + 9x + 20.
        
             
        
        
        
Answer:
Account B   principle for B=400, principle for A=200
Step-by-step explanation:
 
        
             
        
        
        
If the axis is x then you go to y so (6, 5)
 
        
             
        
        
        
Answer:
1. False
2. True
3. True
Step-by-step explanation:
Remark
The point of this question is to encourage you to make use of your calculator. Every calculator can find square roots as far as I know.
Givens
 = 8.367
 = 8.367
 = 8.49
 = 8.49
 = 8.77
 = 8.77
One
Point A is roughly 8.15. The square root of 70 is over 8.3 So square root 70 is to the right of point A. False.
Two
Square root 72 is 8.49. B is 8.3 and C is 8.6. The statement is True
Three
sqrt(77) = 8.77. Point D is 8.75.  The answer is true, but I wouldn't want to bet money on it. The difference is slightly less than 2 100s.