Answer:
Step-by-step explanation:
Let's identify what we are looking for in terms of variables. Sandwiches are s and coffee is c. Casey buys 3 sandwiches, which is represented then by 3s, and 5 cups of coffee, which is represented by 5c. Those all put together on one bill comes to 26. So Casey's equation for his purchases is 3s + 5c = 26. Eric buys 4 sandwiches, 4s, and 2 cups of coffee, 2c, and his total purchase was 23. Eric's equation for his purchases then is 4s + 2c = 23. In order to solve for c, the cost of a cup of coffee, we need to multiply both of those bolded equations by some factor to eliminate the s's. The coefficients on the s terms are 4 and 3. 4 and 3 both go into 12 evenly, so we will multiply the first bolded equation by 4 and the second one by -3 so the s terms cancel out. 4[3s + 5c = 26] means that 12s + 20c = 104. Multiplying the second bolded equation by -3: -3[4s + 2c = 23] means that -12s - 6c = -69. The s terms cancel because 12s - 12s = 0s. We are left with a system of equations that just contain one unknown now, which is c, what we are looking to solve for. 20c = 104 and -6c = -69. Adding those together by the method of elimination (which is what we've been doing all this time), 14c = 35. That means that c = 2.5 and a cup of coffee is $2.50. There you go!
Answer:
Option A is correct.
Solution for the given equation is, 
Step-by-step explanation:
Given that : 
Let 
then our equation become;
.....[1]
A quadratic equation is of the form:
.....[2] where a, b and c are coefficient and the solution is given by;
Comparing equation [1] and [2] we get;
a = 2 b = -1 and c =-1
then;
Simplify:
or
or
and 
Simplify:
y = 1 and 
Substitute y = cos x we have;
⇒
and
⇒ 
The solution set: 
Therefore, the solution for the given equation is, 
So taking this as if there are 13 dozens of cookies. First we do 13 times 12 which would be 156 cookies in total. Then 156 cookies times 2.08 is 324.48
