Answer:
B
Step-by-step explanation:
3x=15
Divide both sides by 3 to isolate the x variable.
x=15/3=5
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!
8,3 is QI
9,-2 is QIV
-3.5,-6 is QIII
Well 5 + 4 is 9, and so if the girls are 5 in the ratio, the fraction would be 5/9. I hope this helps!
system of equations means that we have a given number of equations with the same solutions.
If you only have tables, this means that you need to have one table for each equation:
For example, if you are working only with two variables, x and y, in those tables you can see the pints (x, y) that belong to each equation.
Now, a point (x, y) will be a solution of the system of equations only if it belongs to the data table for each equation
This would mean that if you graph those data sets, the graphs will intersect at the point (x, y) that belongs to all the tables of data.
another way may be using the data in the tables to construct the equations, but you said that you only want to use the tables, so this method can be discarded.
