7. (4 points) Solve k such that the following system21+222-373 = 43X1 - +523 = 2421+エ2+(k2-14)23 = =+2 has infinitely many solutions. (A)k=2(B)k=4(C)k=-4(D)k=8

9. (4 points) Let u = [-1,2] and u = [3,-5] in R2 and let T : R2 -＞ R? R? be a linear transformation such that T'(u) = [-2,1,0] and T(b)= (5,-7,1]. Let [a11 a12] A= a21 022 Q31 be the standard matrix representation of T. Which of the following is TRUE? (A)aL=0(B)az=1(C)az=-2(D)azz=1