We are given two equations: $log(y) = 2log(x) + 1$ $2y = 9x - 1$ We need to find the values of $x$ and $y$ that satisfy both equations. We assume the logarithm is base 10.

AlgebraLogarithmsQuadratic EquationsSystems of EquationsEquation Solving
2025/3/17

1. Problem Description

We are given two equations:
log(y)=2log(x)+1log(y) = 2log(x) + 1
2y=9x12y = 9x - 1
We need to find the values of xx and yy that satisfy both equations. We assume the logarithm is base
1
0.

2. Solution Steps

First, we rewrite the first equation using properties of logarithms.
log(y)=2log(x)+1log(y) = 2log(x) + 1
log(y)=log(x2)+log(10)log(y) = log(x^2) + log(10)
log(y)=log(10x2)log(y) = log(10x^2)
Since the logarithms are equal, we can equate the arguments:
y=10x2y = 10x^2
Now we substitute this expression for yy into the second equation:
2y=9x12y = 9x - 1
2(10x2)=9x12(10x^2) = 9x - 1
20x2=9x120x^2 = 9x - 1
20x29x+1=020x^2 - 9x + 1 = 0
We can factor this quadratic equation:
(4x1)(5x1)=0(4x - 1)(5x - 1) = 0
So the possible values for xx are:
4x1=0=>x=1/44x - 1 = 0 => x = 1/4
5x1=0=>x=1/55x - 1 = 0 => x = 1/5
Now we find the corresponding values of yy using y=10x2y = 10x^2:
If x=1/4x = 1/4, then y=10(1/4)2=10(1/16)=10/16=5/8y = 10(1/4)^2 = 10(1/16) = 10/16 = 5/8
If x=1/5x = 1/5, then y=10(1/5)2=10(1/25)=10/25=2/5y = 10(1/5)^2 = 10(1/25) = 10/25 = 2/5
We now check if these solutions satisfy the second equation 2y=9x12y = 9x - 1:
If x=1/4x = 1/4 and y=5/8y = 5/8, then 2y=2(5/8)=5/42y = 2(5/8) = 5/4 and 9x1=9(1/4)1=9/44/4=5/49x - 1 = 9(1/4) - 1 = 9/4 - 4/4 = 5/4. This solution works.
If x=1/5x = 1/5 and y=2/5y = 2/5, then 2y=2(2/5)=4/52y = 2(2/5) = 4/5 and 9x1=9(1/5)1=9/55/5=4/59x - 1 = 9(1/5) - 1 = 9/5 - 5/5 = 4/5. This solution works.

3. Final Answer

The solutions are (x,y)=(1/4,5/8)(x, y) = (1/4, 5/8) and (x,y)=(1/5,2/5)(x, y) = (1/5, 2/5).

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