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Consider an unknow polynomial which di...

Consider an unknow polynomial which divided by `(x - 3)` and `(x-4)` leaves remainder 2 and 1, respectively. Let R(x) be the remainder when this polynomial is divided by `(x-3)(x-4)`.
If equations `R(x) = x^(2)+ ax +1` has two distint real roots, then exhaustive values of a are.

A

`(-2,2)`

B

`(-oo,-2) uu(2,oo)`

C

`(-2,oo)`

D

all real numbers

Text Solution

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The correct Answer is:
To solve the problem step by step, we will follow the reasoning outlined in the video transcript. ### Step 1: Define the Polynomial and Remainder Let \( P(x) \) be the unknown polynomial. According to the problem, when \( P(x) \) is divided by \( (x - 3)(x - 4) \), it leaves a remainder \( R(x) \). Since the degree of the remainder must be less than the degree of the divisor, we can express \( R(x) \) as a linear polynomial: \[ R(x) = ax + b \] ### Step 2: Use the Remainder Theorem We know that: - \( P(3) = 2 \) (the remainder when divided by \( x - 3 \)) - \( P(4) = 1 \) (the remainder when divided by \( x - 4 \)) Thus, we can write: \[ R(3) = 3a + b = 2 \quad \text{(1)} \] \[ R(4) = 4a + b = 1 \quad \text{(2)} \] ### Step 3: Solve the System of Equations Now we have a system of equations. We can subtract equation (1) from equation (2): \[ (4a + b) - (3a + b) = 1 - 2 \] This simplifies to: \[ 4a - 3a = -1 \] \[ a = -1 \] ### Step 4: Substitute Back to Find \( b \) Now substitute \( a = -1 \) back into equation (1): \[ 3(-1) + b = 2 \] \[ -3 + b = 2 \] \[ b = 5 \] Thus, we have: \[ R(x) = -x + 5 \] ### Step 5: Set Up the Quadratic Equation We need to find the values of \( a \) such that the equation \( R(x) = x^2 + ax + 1 \) has two distinct real roots. This gives us: \[ -x + 5 = x^2 + ax + 1 \] Rearranging this, we get: \[ x^2 + (a + 1)x - 4 = 0 \] ### Step 6: Use the Discriminant Condition For the quadratic equation to have two distinct real roots, the discriminant must be greater than zero: \[ D = (a + 1)^2 - 4(1)(-4) > 0 \] \[ D = (a + 1)^2 + 16 > 0 \] Since \( (a + 1)^2 \) is always non-negative, and adding 16 ensures that the discriminant is always positive. Therefore, the condition is satisfied for all real values of \( a \). ### Conclusion The exhaustive values of \( a \) are: \[ \text{All real numbers} \]

To solve the problem step by step, we will follow the reasoning outlined in the video transcript. ### Step 1: Define the Polynomial and Remainder Let \( P(x) \) be the unknown polynomial. According to the problem, when \( P(x) \) is divided by \( (x - 3)(x - 4) \), it leaves a remainder \( R(x) \). Since the degree of the remainder must be less than the degree of the divisor, we can express \( R(x) \) as a linear polynomial: \[ R(x) = ax + b \] ...
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