SOLUTION: Help pls T_T I'm sorry if this is too much but I really need to solve this to pass T_T , Here's the image link : <a href="http://i39.tinypic.com/2drxwty.png">http://i39.tinypic.com

Question 536033: Help pls T_T I'm sorry if this is too much but I really need to solve this to pass T_T , Here's the image link : http://i39.tinypic.com/2drxwty.png
1) For what value or values of x is (check image) undefined ?
2) If (check image) , express y in terms of x
3) A motorist gets 3 more kilometers per liter when he drives along a highway than when he drives along a city road. Recently he drove 120km on a highway and 180km on a city road and used exactly 23 liters of gasoline. How many kilometers per liter did he get when he drove along the city road ?
4) If (check image) , find x given that k = 3/4
5) Mang Andok can finish a job in 6 hours while Mang Bok can finish the same job in 8 hours . They decided to work together , but they stop to talk and sometimes they argue . Assume that each man's work rate decreases by the same percent. If they complete the job in 5 hours , what is the percent decrease in the men's work rates?
6) Let a and b be distinct real numbers such that (check image)
7) If a nonzero number n increased by 4 times its reciprocal is equal to a real number constant r what is the sum of all possible values of n ?
Image link : http://i39.tinypic.com/2drxwty.png

Please T_T :'(
thanks if you can help

Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
1) For what value or values of x is (check image) undefined ?
x=0
2) If (check image) , express y in terms of x
y=x+1
3) A motorist gets 3 more kilometers per liter when he drives along a highway than when he drives along a city road. Recently he drove 120km on a highway and 180km on a city road and used exactly 23 liters of gasoline. How many kilometers per liter did he get when he drove along the city road ?
let him get x km/l on city road
He gets (x+3)km/l on highway
120/(x+3)+180/x= 23
LCD = x(x+3). Multiply by LCD
120x+180(x+3)=23x(x+3)
120x+180x+540=23x^2+69x
300x+540=23x^2+69x
23x^2-231x-540=0
Find the roots of the equation by quadratic formula

a=23,b= -231c-540

b^2-4ac= 53361 - 49680
b^2-4ac= 103041
= 321

x1=(231 +321)/46
x1= 12
x2=( 231 -321 ) / 46
x2= -1.957
Ignore negative value
speed = 12 mph on city road
15 on highway

4) If (check image) , find x given that k = 3/4
x=k/(k-x)
kx-x^2=k
x^2=kx-k
x^2=k(x-1)
x^2=3/4(x-1)
multiply by 4
4x^2=3x-3
4x^2-3x+3=0
a= 4 ,b= -3 c 3

b^2-4ac= 9 -48
b^2-4ac= -39
= 6.244998i
x1= (3+6.244998i)/8
x1= 0.375 + 0.78062475 i
x2= 0.375 - 0.78062475 i

5) Mang Andok can finish a job in 6 hours while Mang Bok can finish the same job in 8 hours . They decided to work together , but they stop to talk and sometimes they argue . Assume that each man's work rate decreases by the same percent. If they complete the job in 5 hours , what is the percent decrease in the men's work rates?
6) Let a and b be distinct real numbers such that (check image)

7) If a nonzero number n increased by 4 times its reciprocal is equal to a real number constant r what is the sum of all possible values of n ?
Sorry too many questions

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