standard_description: Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations. For example, observe that 4 times a number is always even, and explain why 4 times a number can be decomposed into two equal addends.
problem_activity: A system of linear equations is represented in the graph below.
[IMG]
a.   Write the two equations that represent this system.
b.   What is the solution to the system? Prove this algebraically.


aligns: no