# 7 40 28 3 4 pts there are 2 2 matrices asuch that a2

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3. (4 pts) There are 2×2 matricesAsuch thatA2=-I2. For example, ifA=0-110, thenA2=-I2.Is there a 3×3 matrixAsuch thatA2=-I3? If so, find such anA. If not, show no suchAexists.(hint: use the fact that ifXandYaren×nmatrices then|XY|=|X||Y|)
4. Solve the following systems by finding the inverse of the coefficient matrix.(a) (2 pts)2x-7y=83x-4y=11(b) (4 pts)2x+ 4y-z=15x-3y+ 2z=-56x+ 5y+z=28-1811=1-47-32811=1-32 + 774513Solution