Math Problem Statement
if x+y=8, log_2(xy)=2, then y=
Solution
We are given:
Step 1: Simplify the second equation
From , we rewrite this in exponential form:
So, .
Step 2: Solve the system of equations
We now have two equations:
Let and be the roots of a quadratic equation. A quadratic equation with roots and can be written as:
Substitute and :
Step 3: Solve the quadratic equation
The quadratic equation is:
Use the quadratic formula:
Here, , , and . Substitute these values:
Step 4: Assign and
The roots are and . Since , the values of and are:
or vice versa.
Thus, (assuming ).
Final Answer:
Would you like me to clarify any step further?
Related Questions:
- How do you simplify quadratic equations further when roots involve square roots?
- Can be solved for and without using the quadratic method?
- What if the logarithm had a different base? How would it change the process?
- How does the discriminant of a quadratic equation determine the nature of its roots?
- Can and ever be equal in such cases? Why or why not?
Tip: Always verify solutions by substituting back into the original equations!
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Math Problem Analysis
Mathematical Concepts
Algebra
Logarithms
Quadratic Equations
Formulas
Logarithmic formula: log_b(a) = c implies a = b^c
Quadratic equation formula: t^2 - (x + y)t + xy = 0
Quadratic formula: t = (-b ± √(b^2 - 4ac)) / 2a
Theorems
Properties of logarithms
Quadratic formula theorem
Suitable Grade Level
Grades 9-12