Answer:
"$/km"
Step-by-step explanation:
He wants to model "maintenance cost" with respect to "distance"
Normally,
maintenance cost would be in currency --- dollars, pounds etc.
distance would be in kilometers, miles, meters etc.
We need to find the ratio that has the COST on top and DISTANCE on bottom
Looking at the choices,
We can eliminate 1st and 3rd immediately as it doesn't have COST on top.
That leaves us with
$/km
and
km/$
$ is in fact currency and unit for cost and km is in fact unit for distance. We need the ratio that has $ on top and km on bottom, that's the 2nd option.
So, $/km is the appropriate unit.
Let’s say we have x gallons of brand 1 antifreeze and y gallons of brand 2 antifreeze. We know we need a total of 140 gallons, so one equation to relate the variables would be x+y=140. We also know that our final mixture should have 60% antifreeze, so another equation would be the weighted average of the two brands: .55x+.80y140=.60. (The weighted average is basically multiplying each % (55 and 80) by the number of gallons you have (x and y
) and adding those together, and dividing that by the total number of gallons (140). This equals the % of the final mixture (60).)
Now we have a system of two equations that we can solve.
x+y=140
.55x+.80y140=.60
*rearrange first equation to solve for y
:
y=140−x
*substitute this value in for y
in the second equation:
.55x+.80(140−x)140=.60
*use algebra and solve for x
:
The algebra shouldn’t be too complex, and I’m hoping you’re asking this about the setup rather than the actual algebra, and I’m lazy, and I used a calculator to solve this, and this is probably a long run-on sentence, and I got x=112
.
*plug this in to first equation and solve for y
:
y=140−112=28
x=112,y=28
112 gallons of brand 1 antifreeze, 28 gallons of brand 2 antifreeze. That’s a whole lot of antifreeze.
thanx heyaaaaaa
Find the equation
alrighty, the slope is rise/run
from (21,-3) to (28,-1)
rise is from -3 to -1 or a rise of 2
run is form 21 to 28 or a run of 7
so slope is 2/7
y=2/7x+b
find b which is the y intercept
alirhgty
use (21,-3)
x=21 and y=-3
-3=(2/7)(21)+b
-3=42/7+b
-3=6+b
-9=b
y=2/7x-9
the y intercept is (0,-9
the x intercept is where y=0
0=2/7x-9
9=2/7x
63/2=x
x intercept is (63/2,0) or (31.5,0)
y intercept is (0,-9)
Answer:
Step-by-step explanation:
Point-Slope form is: 
'm' - Slope
(x1, y1) - Point Coordinate
We are given the point of (-1,3) and the slope of 5.
Replace 'm' with 5, 'x1' with -1, and 'y1' with 3:
C) 18 is your answer
Hope this brings you luck ^o^ ^_^
