2x²-5x+8=0
use the quadratic formula, x=(5+√39i)/4 of x=(5-√39i)/4
looks like the second choice is correct.
So we know that the bacteria grows 3x as much every ten minutes. From this we know that it'll be 3 mm in 20 minute. Continuing the pattern, we can figure out that in 40 minutes the bacteria will be 81 mm.
The pattern: 10min - 3 20min - 9 30min - 27 40min - 81
There can be zero solutions, 1 solution or infinite solutions
Answer: " x = 16 ; - 4 " .
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<u>Note</u>:
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-16 , +4 = -12 .
-16 * 4 = -64
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(x - 16)(x + 4) = 0 ;
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x = 16 ; - 4 .
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