Finding the derivative of implicit function x * 3 + y * 3-3axy = 0

Finding the derivative of implicit function x * 3 + y * 3-3axy = 0

Derivation of X
There is 3 (x ^ 2 + y ^ 2Y '- ay axis') = 0
So we have (x ^ 2-ay) + (y ^ 2-ax) y '= 0
So y '= (ay-x ^ 2) / (y ^ 2-ax)

What is the derivation of X on both sides of the equation f (x, y) = 0

Consider y as a function y (x) with X
F(x,y)=F(x,y(x))=0
If x is derived on both sides, the left side is equivalent to f (x, y (x)), and the right side is the constant 0, which is still 0

E ^ xy = x + y for the derivation of the equation on both sides

e^xy=x+y
Both sides of X at the same time to obtain the derivative
e^(xy)·(xy) '=1+y '
e^(xy)·(y+xy ')=1+y '

An Olympic math problem in primary school
Party A and Party B do math problems together. If Party A does four more problems as much as Party B does, and if Party B does six more problems, that is three times as much as Party A does, how many problems does Party A do? How many problems does Party B do?
Note: do not use the equation solution, but use the solution

Party A and Party B do math problems together. If Party A does four more problems as much as Party B does, and if Party B does six more problems, that is three times as much as Party A does, how many problems does Party A do? How many problems does Party B do
According to the meaning of the question, B does 4 more questions than a
If B does 6 more questions than a: 4 + 6 = 10, which is 3 times of A
So a is: 10 / [3-1] = 5 questions
B: 5 + 4 = 9

1. 2, 3, 4, 5, 6, 7, 8, 9, fill in addition and subtraction in each number to make it equal to 100, and each number can only be used once?
What should I do?

123-(4+5+6+7)+8-9=123-22+8-9=100

Seeking 20 application questions of linear equation of one variable (with answers) is extremely urgent~~~
For the first day of one yuan equation 20, to have an answer, 100000 urgent, please Pro active help ah~~~~

In order to save energy, a unit charges the monthly electricity fee according to the following regulations: if the electricity consumption is not more than 140 kwh, the charge is 0.43 yuan per kwh; if the electricity consumption is more than 140 kwh, the charge is 0.57 yuan per kWh for the excess part. If the average electricity charge of a user in April is 0.5 yuan per kWh, how much should the user pay in April

1+1+2+3+4+5+6+7+8+9+10+100+1000+10000+.

1 to 9 is the sum of the first n terms of the arithmetic sequence, and 10 is the sum of the first n terms of the arithmetic sequence

50 minus x plus 3 equals 3 (x plus 3)

50-x+3=3(x+3)
53-x=3x+9
3x+x=53-9
4x=44
x=44÷4
x=11

There is an English book and three math books on the desk

There is an English book and three math books on the desk.

The scale of a map is 1:1000 000. If a person walks 1000 meters on the ground, what is the distance on the map?

1000 m = 100000 cm
1000000 △ 100000 = 10 cm
Ten centimeters
If you understand and solve your problem,