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Question 1. The vector (a,-1)   is a linear combination of the vectors (1,4),   (-4,-16)  if and only if
a) a=4  
b) a=1/4  
c) a=-4  
d) a=-1/4  
e) a  
Question 2. For which a   has the following system of linear equations no solution?

2x+2y-2z=0x+y+az=ay+z=a  

a) a=1  
b) a=3  
c) a=-1  
d) it has a solution for all a  
e) a=-2  
Question 3. Determine the matrix X   satisfying 5B+X=2A,   if A=(1,-3,20,4,11,-1,0),   B=(0,2,-14,-5,01,-2,1).  
a) X=(2,4,-120,-17,27,-12,5)  
b) X=(1,-1,14,-1,12,-3,1)  
c) X=(2,-16,9-20,33,2-3,8,-5)  
d) X=(2,-8,5-4,13,21,1,-1)  
e) X=(1,-13,7-20,29,1-4,9,-5)  

Evaluate