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.
Answer:
it's answer is 4:1
Because length of small intestine is 6 m and length of large intestine is 1•5m
So 6/1•5 =4:1
Answer: 94 child tickets
<u>Step-by-step explanation:</u>
Let x represent child tickets
Let y represent adult tickets
Cost Equation: 5.70x + 9.75y = 1306.10
Quantity Equation: x + y = 173
Solve the system of equations using the elimination method:
Multiply the Quantity Equation by -5.70
5.70x + 9.75y = 1306.10
<u> -5.70x - 5.70y</u> = <u>-986.10</u>
4.05y = 320.00
<u> ÷4.05 </u> <u>÷4.05 </u>
y = 79
x + y = 173
x + 79 = 173
x = 94
Answer:
9a - 2b
Step-by-step explanation:
6a - 6b +3a +4b . . . . . . . we assume your _ is supposed to be -
= a(6 +3) +b(-6 +4)
= 9a -2b
Let the average cost of car in 2009 be $x, then the average cost of a car in 2013 is 2x - 5
25,000 = 2x - 5
2x = 25,000 + 5 = 25,005
x = 25,005/2 = $12,502.50
