Let x be the amount invested at 9% and y the amount invested at 6%.
Then we have:
I) x + y = $14,929
II) 0.09x - 0.06y = $1,139.91
First, we multiply equation II by 100:
9x - 6y = $113,991
Now, we add to it 6 times equation I:
15x = $203,565
x = $13,571
Now, we replace x in equation I to find y:
$13,571 + y = 14,929
y = $1,358