Answer: x=15
Step-by-step explanation:
Equation: 107=(9x-115)+(4x+27)
Step 1: 9x+4x-115+27=107
Step 2: 13x-115+27=107
Step 3: 13x-88=107
Step 4: 13x-88+88=107+88
Step 5: 13x=195
Step 6: 13x/13=195/13
x=15
Answer:
for 18 x is 6 and for 20 it is 11
Step-by-step explanation:
For 18, since -1+2x and 5+x is the same thing, set up and equation. WE can simplify to -1+x=5 and then we get x=6
For 20, 18 is 11 since 18=-4+2x. If we simplify we get 22=2x then we can use algebra to say that x=11
Hope this helps :)
A petri dish is simply a circle; thus, we use the formula of the area of the circle which is <span>πr^2.
Given r = 40 mm
A = </span>π(40)^2 = <span>5026.55 sq. mm
</span>
Population density = bacteria count / area
PD = 2,100 / <span>5026.55
PD = </span><span>0.417782 bacteria / mm sq.
Therefore, the answer is approximately 0.418 </span><span>bacteria per square millimeter.</span>
