v = c1v1 + c2v2 [4 5] = c1[1 3] + c2[4 -2] [4 5] = [c1*1 c1*3] + [c2*4 c2*-2] [4 5] = [c1 3c1] + [4c2 -2c2] [4 5] = [c1+4c2 3c1-2c2] Equating first components give the equation 4 = c1 + 4c2 Equating second components gives the equation 5 = 3c1 - 2c2 So we have this system of equations: 4 = c1 + 4c2 5 = 3c1 - 2c2 Or c1 + 4c2 = 4 3c1 - 2c2 = 5 Solve that system of equations and get c1 = 2, c2 = 1/2 Edwin