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Jun 15, 2024
 #1
avatar+1767 
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Jun 15, 2024
 #1
avatar+1767 
0
Jun 15, 2024
 #1
avatar+1767 
0
Jun 15, 2024
 #1
avatar+1767 
0
Jun 15, 2024
 #1
avatar+1767 
0
Jun 15, 2024
 #1
avatar+1767 
0

Problem 1:

 

We can leverage the concept of sum and product of roots in quadratic equations.

 

Since x = 4 is a root, we know that f(4) = 0. This translates to:

 

16a + 4b + a = 0

 

Combining like terms, we get: 17a + 4b = 0 (Equation 1)

 

We are also given that f(x) = ax^2 + bx + a. Since a ≠ 0, we can rewrite f(x) by factoring out a:

 

f(x) = a(x^2 + bx/a + 1/a)

 

We know that one root is x = 4. This means that (x - 4) is a factor of f(x). Let's rewrite f(x) using this information:

 

f(x) = a(x - 4)(x + r) for some constant r (since the product of the roots is cr)

 

Equating both ways of expressing f(x), we get:

 

a(x^2 + bx/a + 1/a) = a(x - 4)(x + r)

 

Expanding both sides:

 

ax^2 + bx + a = ax^2 - (4a + r)x + 4ar

 

Equating the coefficients of like terms on both sides, we get:

 

b = - (4a + r) (Equation 2)

 

Now we have two independent equations (Equation 1 and Equation 2) with unknowns a, b, and r. We can use the fact that one root is x = 4 (reflected in Equation 1) to solve for the other root.

 

Since we're looking for the other root, let's try to eliminate a and b from the equations and solve for r.

 

From Equation 1: b = -17a/4

 

Substitute this into Equation 2:

 

-17a/4 = - (4a + r)

 

Solve for r:

 

17a/4 = 4a + r

 

r = 17a/4 - 4a

 

r = a/4

 

Now that we know r (product of roots), we can find the other root itself. Since the product of roots (cr) is also equal to f(4) (which is 0 in this case), we have:

 

(4)(other root) = 0

 

Since a ≠ 0, this implies the other root must be:

 

Other root = 0

 

In conclusion, the other root of the equation f(x) = 0 is x = 0.

Jun 15, 2024

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