Fractional practice questions? Urgent! 5. Fractional practice questions? Urgent!

1.Assuming that the original plan is to repair the road xm per day, then 2400 x-2400 2Assuming that the original plan had x people involved in tree planting, then.

180/x-180/

x=30 gives x=50

3.It takes X days for the engineering team to complete the work, then.

20(1/x+1/2x)=1

x=30, then team A uses 30 1000 = 30000, team B uses 2 30 550 = 33000

With team A, 30,000 yuan.

The first fraction numerator denominator multiplies (x-1), the third numerator denominator multiplies (x-1) (x+2) and then the fraction is added The above numerator is x(x-1)(x+2)-3-(x-1)(x+2) Split and then factor to get (x-1) (x+2) (x+3) and the denominator are approximated.

Through-score (x 2+2x-3) (x-1)(x+2) -1

The molecule proposes that x-1 is eliminated and the rest is not written.

1 x^2+2x+1 x^2-1= --/ --x+2 x+2 x-11 (x+1)^2 x-1= --x+2 x+2 x^2-11 (x+1)^2 x-1= --x+2 x+2 (x-1)(x+1)1 x+1

x+2 x+2

1-(x+2)

x+2 because x2 = 4

So x= 2

When x=+2.

1 The solution of this equation is -

2. There is no solution when x=-2!

After figuring out the fraction and changing the denominator to the same, it's easy to do.

=(2x+2-3)/(x+1)+(3x+6-5)/(x+2)-(5x-5-6)/(x-1)

2(x+1)-3]/(x+1)+[3(x+2)-5]/(x+2)-[5(x-1)-6]/(x-1)

2-3 (x+1)+3-5 (x+2)-5+6 (x-1)=-3 (x+1)-5 (x+2)+6 (x-1)=-( 2x 2-15x-23) (x 3+2x 2-x-2)

Solution: (2x-1) (x+1)+(3x+1) (x+2)-(5x-11) (x-1).

(2x-1)(x+2)+(3x+1)(x+1)]/(x+1)(x+2)-(5x-11)/(x-1)

5x^2+7x-1)/(x^2+3x+2)-(5x-11)/(x-1)

(5x^2+7x-1)(x-1)-(5x-11)((x^2+3x+2)]/(x^2+3x+2)(x-1)

-2x^2+15x+23)/(x^3+2x^2-x-2)

The correct answer is as above, welcome to adopt! Thank.

Since the quantity and the total price are not equal, the average unit price of rice purchased by A and B should be calculated separately, and the comparison can be compared Answer: Solution: Let the unit price of rice for two times be x yuan kg and y yuan kg (x 0, y 0, x≠y), then A spent an average of x+y 2 yuan per kilogram, and B spent an average of 2 1 x+1 y yuan per kilogram

And x+y 2-2 1 x+1 y =x+y 2-2xy x+y=(x+y)2 2(x+y)<0, so B's purchase method is cost-effective Comments: The key to solving this problem is to obtain the average unit price of rice and simple wax purchased by A and B; Note: When the quantity is different, the average unit price = total price Total quantity

1. Gurgou to Lixian: t=30 x=30 x Lixian to Wenchuan: speed v=(1+1 9)x=10 9x, time=60 (10 9x)=54 x 2, known by the title:

The total time is 24h-(14h28min+2)+23h15min - 1h=30 x+ 54 x 29h47min=84 x (29*60+47) 60=84 x x =5040 1787 I feel that the book will not produce results for such a tangled problem, the calculation process should be correct, and the result is generally better for you to calculate by yourself.

Step on it first, and think about it tomorrow and then Fu Pei.

Come back to the birds. The value of this fraction is 0

Process: A (b+c)+b (c+a)+c (a+b) =1 can be reduced to: a (b+c)=1 -b (c+a)-c (a+b).

b (c+a) = 1 -a (b+c) - c (a+b).

c/(a+b) =1 -a/(b+c)-b/(c+a)

a*2/(b+c)+b*2/(c+a)+c*2/(a+b)

a×a/(b+c)+b×b/(a+c)+c×c/(a+b)

Bring in the algebraic formula that has been made and get).

a×[1 -b/(c+a)-c/(a+b)]+b×[1 -a/(b+c）-c/(a+b) ]c×[1 -a/(b+c)-b/(c+a)]

A-ab (C+A)-AC (A+B)+B-AB Mu Hall Stool (B+C)-BC (A+B)+C-AC (B+C)-BC (C+A).

Do you understand? It's a bit complicated, so let's put the same denominator and merge together, a, b, and c aside. ）

ab-bc)/(c+a)+(ac-bc)/(a+b)+(ab-ac)/(b+c)+a+b+c

The numerator of a single fraction proposes a minus sign and a common factor, a, b, c are still set aside).

b(a+c)/(a+c)]+c(a+b)/(a+b)]+a(b+c)/(b+c)]+a+b+c

Approximate to get )-b-c-a+a+b+c

Hope satisfied, thank you

Xie has Huaiqiao Tsai lead Wang Zhi AC 2=A 3+ab 2+b 3+b 2c+abc

Assuming a = 1 and c = 1, the above formula is given with desensitization to obtain b = -1 or b = 0

then the solution is the original formula = 2

Because 3x 2-3=3(x 2-1)=3(x-1)(x+1), the common factor of 3x 2-3 and x+1 is x+1, and the simplest common denominator is 3x 2-3, i.e., a=x-1, b=3x 2-3, and because b a=3, i.e., x+1=1, so, x=0, therefore, the values of these two fractions are -1 3,2