Well, this problem is best solved by setting up a system of two linear equations.
A linear equation can be defined
y=mx+b
where
b=initial value (when x=0), and
m=rate of increase or decrease.
In the given example, the x-axis represents hour, and the y-axis, number of cells.
Chemical #1
initial value = b = 12000 cells
rate = m = -4000 / hr
The equation is therefore
y1=-4000x+12000......................(1)
Similarly, for chemical #2
initial value = b = 6000 cells
rate = m = -3000 / hr
The equation is therefore
y2=-3000x+6000 .......................(2)
The time the two will have an equal sized colony would represent the solution of the system of equations (1) and (2), i.e. when y1=y2
which means
-4000x+12000 = -3000x+6000
transpose and solve for x
4000x-3000x = 12000-6000
1000x=6000
x=6 hours.
At 6 hours from the start,
y=-4000x+12000 = -4000*6+12000 = -24000+12000 = -12000 cells
So the solution is x=6, y=-12000, or (6,-12000)
Physical interpretation
Since cells cannot have a negative number, the two are actually equal before six hours, when they are both zero.
Case 1: y=0 when x=3
Case 2: y=0 when x=2
Therefore, after three hours, both trials will have zero cells.
You have to judge whether to give the mathematical solution (x=6,y=-12000) or the physical interpretation (x=3, y=0) as the answer.
The GCF of 10 and 6 is 2. May this will help you.
1) Volume of the box = 90*45*45=<span>182250 cm³
2) filled with soil = 0.85*</span>182250= <span>154912.5 cm³
3) </span>182250 cm³-154912.5 cm³=<span>27337.5 cm³ not filled
4) </span>27337.5 cm³/28316 cm³=0.9654 ≈ 1 bag
Answer:
No, he is incorrect because he forgot to multiple the negative by the x, and only multiplied 3 by x instead of -3 by x.
Step-by-step explanation:
The correct re-write of this expression is:
-3x - 30
