F(x)= -2x-4 , x=-3
plug in -3, where ever x appears in the function
f(-3)=-2(-3)-4
f(-3)=6-4 <-- remember two negatives make a positive when multiplied or divided.
f(-3)=2
........and since this is not an answer, are you sure you copied it down correctly? or can you answer non?
The answer is 160 because as you stated in the question the number of bacteria doubles every five minutes, and after 10 minutes there are 40. Therefore, after 15 minutes there are 80 (40 doubled is 80), and after 20 (another 5 minutes), the number of bacteria is the double of 80, which is 160.
- Hope I helped :)
- PeaceLoveHappiness
Y = 10^x
log y = log 10^x
log y = x log 10
D. 79/9 is the correct answer