Answer:
A
Step-by-step explanation:
Those two lines are the same. If you divide the second equation by 2, you will end up with the first equation. A system of linear equations cannot have two of the same line.
5 + 5 + 10 = 20
x + y + z = 160
5 × 80 : 5 × 80 : 10 × 80
400 : 400 : 800
Let's name the number 'n'. Now write an equation. 7*n +n^2 =12Now you can form a quadratic. n^2 +7n-12=0. Now you can use a myriad of methods to solve it. If you still need help, just message me.