Solution:
Let A=∣x2−12x+20∣.
The equation is:
(Alogx2)−1+logx=A1+log(1/x)
First, A≥0 and x=0 (since logx2 is defined for x=0).
Also, logx is defined for x>0.
So, x>0.
Now, log(1/x)=−logx, so 1+log(1/x)=1−logx.
The equation becomes:
(Alogx2)−1+logx=A1−logx
Recall that Alogx2=A2logx=(Alogx)2.
So,
((Alogx)2)−1+logx=A1−logx
(Alogx)2(−1+logx)=A1−logx
A2(−1+logx)logx=A1−logx
If A=0, then ∣x2−12x+20∣=0⟹x2−12x+20=0⟹x=2 or x=10.
Check x=2:
A=0, logx=log2>0, logx2=2log2>0.
Left side: 0something is 0 if exponent >0, 1 if exponent =0, undefined if exponent <0.
But A=0, so 0something is 0 if exponent >0.
Right side: 01−log2. 1−log2<1, so exponent <1.
But 0a=0 for a>0, undefined for a≤0.
So, x=2 and x=10 do not give valid solutions.
Now, for A>0, A=0:
Since A>0, Ak is defined for all real k.
So, equate exponents:
If A=1, then Ap=Aq⟹p=q.
So,
2(−1+logx)logx=1−logx
Let y=logx (so x>0):
2(y−1)y=1−y
2y2−2y=1−y
2y2−2y+y−1=0
2y2−y−1=0
2y2−y−1=0
Solve for y:
y=41±1+8=41±3
So y=1 or y=−21.
So logx=1⟹x=10, logx=−21⟹x=10−1/2=1/10.
Recall A=∣x2−12x+20∣.
If A=1, then Ap=Aq for any p,q.
So, A=1⟹∣x2−12x+20∣=1.
x2−12x+20=1 or x2−12x+20=−1
x2−12x+19=0
x=6±36−19=6±17
x2−12x+21=0
x=6±36−21=6±15
But x>0.
So, possible x values:
6+17, 6−17, 6+15, 6−15.
Check if these are positive:
17≈4.12, 6−4.12=1.88>0
15≈3.87, 6−3.87=2.13>0
So all four are positive.
Now, check if x=10 or x=1/10 gives A=1.
For x=10:
A=∣100−120+20∣=∣0∣=0=1
For x=1/10:
x2=1/10, x2−12x+20=1/10−12/10+20
This is not ±1.
So, x=10 and x=1/10 are not among the A=1 solutions.
Now, check if A>0 for x=1/10:
x=1/10, x2=1/10, x2−12x+20=1/10−12/10+20
12/10≈12/3.16≈3.8
So 1/10−3.8+20≈0.1−3.8+20=16.3
So A>0.
So, x=1/10 is valid.
So, the solutions are:
- x=1/10
- x=6+17
- x=6−17
- x=6+15
- x=6−15
Total: 5 real numbers x.
Answer: 5