When calculating a number divided by 1 / 6, it is mistakenly regarded as multiplying by 1 / 6, and the result is 8 / 9. What is the correct result

When calculating a number divided by 1 / 6, it is mistakenly regarded as multiplying by 1 / 6, and the result is 8 / 9. What is the correct result

8 / 9 times 1 / 6 = 16 / 3
So this number is 16 / 3
16 / 3 divided by 1 / 6 = 32
So the correct result is 32

Known 2009x + 2010Y_ 2010 = 0; if XY is opposite to each other, then x =? Y =?

2009x+2010y_ 2010=0
2009 (x + y) + y-2010 = 0, because XY is opposite to each other, so x + y = 0
So y-2010 = 0
y=2010
X=-2010

In a subtraction, the subtraction is two fifths of the subtracted, and the difference is a few percent of the subtracted
Please add the method of doing questions

3/5
A - 2/5A = 3/5A

It is known that X & # 179; - Y & # 179; = 19, X & # 178; y + XY & # 178; = 21
Find the value of (X & # 179; + 2Y & # 179;) - 2 (X & # 179; - 2XY & # 178; + X & # 178; y) + (Y & # 179; + 4x & # 178; y-2xy & # 178; - 2x & # 179;)

（x³+2y³）-2（x³-2xy²+x²y）+(y³+4x²y-2xy²-2x³)
=x³+2y³-2x³+4xy²-2x²y+y³+4x²y-2xy²-2x³
=-3x³+3y³+2x²y+2xy²
=-3(x³-y³)+2(x²y+xy²)
=-3×19+2×21
=-57+42
=-15

On tree planting day, each student in a class should plant 6 trees on average. If only female students complete the task, each student should plant 15 trees. If only male students complete the task, how many trees should each student plant?

Suppose there are x girls and Y boys,
6（x+y)=15x
9x=6y
x=2y/3,
6 (x + y) / y = 6 (2Y / 3 + y) / y = 10 trees

If y = the absolute value of X + 1, and X is greater than or equal to negative 2, less than or equal to 2, find the maximum and minimum value of Y, and solve similar problems

x≤2;x≥-2;
x+1≤3;x+1≥-1;
After taking the absolute value, the maximum value is 3 and the minimum value is 0;
It's a step-by-step approach to the function

There are 55 students in grade 3 of Xinxing primary school. How many students' birthdays are in the same week?

There are 52 weeks in a year. First of all, suppose that one student has a birthday in one week, and the remaining three students are randomly divided into one week, two weeks or three weeks, so at least two students have their birthdays in the same week

(A-3) ^ 2 + (3b + 1) ^ 2 = 0 to simplify (a + b) (a-b) - (a + b) ^ 2-2b ^ 2

∵(a-3)^2+(3b+1)^2=0
If both values are nonnegative and sum is 0, then both are 0
∴a-3=0,3b+1=0
∴a=3,b=-1/3
∴(a+b)(a-b)-(a+b)^2-2b^2
=a²-b²-(a²+2ab+b²)-2b²
=a²-3b²-a²-2ab-b²
=-4b²-2ab
Substituting a = 3, B = - 1 / 3
Original formula = - 4 * 1 / 9-2 * 3 * (- 1 / 3) = 14 / 9

(1) The car and the truck set out at the same time from two places 350 kilometers away, and they ran in opposite directions. After 2.5 hours, the two cars met, and the car traveled 80 kilometers per hour
How many kilometers per hour does the truck travel?
(2) The car and the truck set out at the same time from two places 350 kilometers apart, and they went in opposite directions. The car traveled 80 kilometers per hour and the truck 60 kilometers per hour. After a few hours, the two cars met on the way?
(3) The car and the truck start at the same time from two places 350 kilometers apart, and travel in opposite directions. The car travels 80 kilometers per hour, and the truck travels 60 kilometers per hour?
(solving equations and setting solutions)

The speed of the truck is x km / h
(1) 80*2.5+2.5x=350
X = 60 km / h
(2) Meet in Y hours
80*Y+60*Y=350
Y = 2.5 hours
(3) After Z hours, the distance is 70 km
80Z+60Z=350-70
Z = 2 hours

It is known that a and B are two real roots of the equation 2x + x ^ 2-5 = 0, a ^ 2 + AB + 2A =?

x²+2x-5=0
Substituting x = a, we get:
a²+2a-5=0
a²+2a=5
According to Veda's theorem,
a*b=-5
a²+ab+2a
=(a²+2a)+ab
=5+(-5)
=0