Answer:
x = 9(4)-34 = 2
Step-by-step explanation:
I have a feeling I've seen this question before
anyway
A=number of hours that plan A is
B=number of hours that plan B is
so
on wednesday, 7hr
5A and 6B so
5A+6B=7
on thursday, 3 hours
3 of A and 2 of B
3A+2B=3
so we gots
5A+6B=7
3A+2B=3
elimination
eliminate B's
multiply 2nd equation by -3 and add to 1st equation
5A+6B=7
<u>-9A-6B=-9 +</u>
-4A+0B=-2
-4A=-2
divide both sides by -4
A=1/2
A=0.5
sub back
3A+2B=3
3(0.5)+2B=3
1.5+2B=3
minus 1.5 both sides
2B=1.5
divide by 2 both sides
B=0.75
plan A lasts 1/2 hour or 0.5 hour or 30 mins
plan B lasts 3/4 hour or 0.75 hour or 45 mins
Id take a guess and say line 1 because the rest looks correct
The answer is B) The initial number of bacteria is 57, and the growth rate is 31% per hour.
The expression shown is an <em>exponential expression</em>. An exponential expression usually takes the form 
, as this one does. A represents the <em>initial value</em>, in this case-the initial number of bacteria. B represents the <em>growth rate</em>. When it is an increasing growth rate, it will begin with 1, because it will have everything it had before, plus the percent increase, the decimal portion. In this case, a=57, and b=0.31.
Hope this makes sense!
