Which mathematical property is demonstrated 7 + 9 + 3 = 7 + 3 + 9

Matt and brian were solving a system of equations. they both noticed that the two lines had the same slope. brian said that because each line in the system had the same slope, the two lines had to be parallel, which meant the solution to the system was "no solution" matt disagreed, and said they should also look at the y-intercepts before determining how many solutions there were. who is correct?

What is the value of x in the equation 1.5x+4-3=4.5(x-2)?

Joey is asked to name a quadrilateral that is also a rhombus and has 2 pairs of parallel sides.should be his answer