Think of each equation as a βrowβ of numbers multiplyingΒ β(xyβ).Β Put the x- and y-coefficients into a matrix so that multiplying recreates the left-hand sides.
β
AAxβ=(a3β23β)=(a3β23β)(xyβ)=(34β)β
β
So the system isΒ βAx=bβΒ withΒ βA=(a3β23β).