Need help proving this

4 Computation a Let M = b c d , and let T : K2 -> K2 be the associated linear transforma- tion. Prove that M2 - (a + d) M E span In lecture, I defined the vector space Lr, where T : V - V is a linear transformation. A few of the problems on this assignment are about the 0 dimension of Lr; I will write ((7) to refer to the dimension of Lr to make notation less clunky: ((T) : = dim LT