No, we do not multiply the first equation by 2 and then add it to the second equation. We have to multiply the first equation by 4.
To illustrate this point, consider system A:
If we multiply the first equation by 2, we get
Now, if we replace the second equation with the sum of the second equation and , we get
which simplifies to
This is not an equivalent system to System B. We can see that we ended up with a 2y = 4 equation.
In order to end up with a 2x = 10 second equation, we have to multiply the first equation of system A by 4 to get
If we replace the second equation with the sum of the second equation and , we get
which simplifies to
Otherwise, you are correct. The solution to system B is the solution to system A. Adding an equation to another does not change the system.
First I would distribute the left part like so:
12x - 18 - (5x + 7)
Then I would distribute the right side like so: (I'm just distributing a negative sign)
12x - 18 - 5x - 7
Then I combine like terms like so: (12x and -5x)
7x - 18 - 7
Then I would combine the other like terms like so: (-18 and -7)
7x - 25
I hope that helps! Feel free to let me know if you have any questions! :3
- mathwizzard3
Answer:
-14x+21
Step-by-step explanation:
-7(2x-3)
-14x+21
The minimum would be 15. I'm sorry if I'm wrong, but I'm pretty sure that's the answer.
The total number of rocks collected:
r + 2r + 2r - 5
Rocks collected by Maria and Javier:
3r
The difference between the number of rocks collected by Pablo and Maria:
r - 5
The sum of rocks collected by the boys:
4r - 5
The number of rocks collected by Pablo and Maria:
r + 2r - 5
