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MATH 2341 QUIZ 7A FALL 2018 NAME, SOLUTIONS. (25 POINTS) NO CREDIT GIVEN UNLESS THE WORK IS SHOWN. ANSWERS DIRECTLY FROM YOUR CALCULATOR WILL RECEIVE NO CREDIT. 4-7) i -K 2 18-41 37 | I Lett4=|-9 6 al} 5 jem e- 29 -17 13 |. Find (AB- 30) 8 -5| a -23 26-43, (5 points) 4-7 r9 3 8 36-49 -12+42 32+28 13. 30 «60 ap=|-9 6]/, 6 al -814+42 27-36 -72-24]-|-39 -9 -96 8 -5s|- 72-35 -244+30 64+20 37 6 84 54-123 111 -13 30 60 54-123 111] 3c =| 87 -S5l1 39 AB-3C = |-39 -9 -96|-| 87 -S]1 32: -69 78 -129 37 6 84] [-69 78-129) [-67 153 -51 = |-126 42 -135 106 -72 213 -67 -126 106 Therefore, (4B- 3C)' = | 153 42 -72 -51 -135 213 12 -5 3 6 2 Lett4=]/0 0 2 O —-8). Find rref(4) and rank (4). (3 points) 24 -5 6 -8 12-53 6 12-5 3 6 2Ri +R, 12k: |O O 1 0 -4]/-5R2 +R: |O 0 1 0 -4 00 5 O —20 00 0 0 0 12 03 14 SR2~Ri}0 O 1 O 4] = rref{4) and rank (4) = 2 (two nonzero rows in rref) 0000 0