Weird answer for "Solving systems of linear equations" in SAT math section
This was the math problem.
1.5a - 4.5b = 3(a + b)
5.5b = 5(b - a) + 2.5a
Consider the system of equations above. If (a,b) is the solution to the system, then what is the value of b - a?
This is the solution Khan Academy gave.
A part of the solution confused me. I understood how they reached 5.5b = 30b - 12.5b, but I don't understand how b = 0. Shouldn't b = 12?
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