Solving the equation (LG x) & sup2; - 2lg x-3 = 0 I know, but I hope you can still write the whole process, and the score is yours.

Solving the equation (LG x) & sup2; - 2lg x-3 = 0 I know, but I hope you can still write the whole process, and the score is yours.

Let LG x = y, then the original formula is y ^ 2-2y-3 = 0
y1=3,y2=-1
∵lg x＞0
Ψ Y2 rounding off
That is LG x = 3
x=1000

LG (x / 10) = - 2-2lg x solution x
Solve x, such as the problem

lg(x/10)=-2-2lg x
lgx -1=-2-2lgx
3lgx=-1
lgx=-1/3
x=10^(-1/3)

Solving the equation LG (x + 7) - 3lg2 = 2lg3

lg(x+7)-3lg2=2lg3
lg(x+7)-lg8=lg9
lg[(x+7)/8]=lg9
So there are:
(x+7)/8=9
x+7=72
The solution is as follows
x=65

What is the solution of the equation LG (27 + x ^ 2) = 2lg (3-x)

lg(27+x²)=lg(3-x)²=lg(9-6x+x²)
So 27 + X & # 178; = 9-6x + X & # 178;
6x=-18
x=-3

Finding LG (AB) 9 (loga ^ B + logb ^ a) from 2lg2x-lgx ^ 4 + 1 = 0

Alas

Let u = R, a = {x | X & # 178; - 2x-15 ＜ 0}. B = {x | y = LG (x + 2)}, then a ∩ B is?

（-2,5）

Let y = x & # 178; - ax + B, a = {x | Y-X = 0}, B = {x | y-ax = 0}, if a = {- 3,1}, use enumeration to represent set B

There are positive and negative (2 √ 2) - 3 in set B
X in the set a is the solution of the equation x = x ^ 2-ax + B, because Y-X = 0, y = X
So we take in x = - 3, x = 1 and get the values of a and B
X in B is the solution of the equation AX = x ^ 2-ax + B. take the values of a and B into this equation
And then we can work out X

The known set a (x, y) ax + y = 1, B = (x, y) x + ay = 1, C = (x, y) x square + y square = 1
When a is a value, the intersection C of (A and b) is a binary set, and what value is a ternary set

Ax = (1-y) / ABX = (1-ay) a and B (1-y) / A and a (1-ay) / a if a is brought into C to get a binary set (2 elements a, y) if B is brought into C to get a ternary set (3 elements a, a ^ 2, y), so if you want to get a binary set, then a and B should = a, that is, a = B. If you want to get a ternary set, then a and B should contain B

Given that (1,2) belongs to a ∩ B, set a = {(x, y) | ax-y & # 178; + B = 0}, B = {(x, y) | X & # 178; - ay-b = 0}, find the real number a, B

Because a and B are (1,2)
So x = 1, y = 2 are the solutions of two equations in AB set
Bring in
Two new equations are obtained
a-4+b=0
1-2a-b=0
The solution is a = - 3
b=7

We know that a = {x | X & # 178; + x = 6} and B = {y | ay + 1 = 0, y ∈ r},
Satisfy B & # 8838; (it should be a U rotated 90 degrees to the right plus an unequal sign, but it can't be typed out), and find all the values that can be obtained by finding the real number a

∵ X & # 178; + x = 6, x = 2 or - 3
And ay + 1 = 0
(1) B is not an empty set
Let y = 2 or - 3
The solution is a = - 1 / 2 & 1 / 3
(2) B is an empty set
a=0
In conclusion: a = 0, - 1 / 2,1 / 3