9514 1404 393
Answer:
no solution
Step-by-step explanation:
Adding the two equations gives you ...
(-7x -4y) +(7x +4y) = (11) +(20)
0 = 31 . . . . . . false
No values of the variables will make this equation true. There is no solution.
Answer:
0.74 to 6.06
Step-by-step explanation:
The groups are independnet,
SE(xh bar-xa bar)=sqrt [sh^2/nh+sa^2/na]=sqrt [10.1^2/80+10.3^2/80]=1.61
At df=157, the t critical is 1.65
90%c.i=(xh bar-xa bar)+-tcritical SE(xh bar-xa bar)
=(25.2-21.8)+-1.65*1.61
=0.74 to 6.06
Answer - D.
you basically find the equation of the line first and eliminate the wrong answers...
Strategy: before u do any of this, label your coordinates as (X1,Y1) and (X2,Y2) and u can choose any of ur points to be as x1 or x2 or y1 or y1...
basically, I'll choose (6,7) as (x1,y1) and (2,-1) as (x2,y2). SO,
First you have to find the gradient (m) of the line.
you do this by using the formula m = Y2-Y1 / X2-X1 (where '/' is division sign) ....
Put the numbers in their respective places and your gradient will be 2x. we put the x after our number to represent it as a gradient as the straight line formula is y = mx+c and you've found the m.
NOW.
use the formula Y-Y1=m(x-x1) to find the equation of the line.Again u can use any Y1 and X1 here but remember your m is 2
replace the digits and solve...Hopefully you'll get sth like this if you use the points (6,7):
Y-7 = 2(x-6) ....
y=2x-12+7...
Y=2x-5! <<<< this is your straight line equation!
Now all u gotta do is rearrange all your options into y = mx+c.
D. is incorrect as it gives us y=2x+5 and not y = 2x-5 unlike the others
Hope you get it!
Decibel is directly proportional to number of cars passing the point. That is,
69 db ----- 139 cars
x db ----- 17 cars
x = number of cars passing the point per minute on a weekend.
Then,
x= (69*17)/139 = 8.43 db ≈ 8 db
