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The equation ax^(2) +bx+c=0 where a,b,c ...

The equation `ax^(2) +bx+c=0` where a,b,c are real numbers connected by the relation `4a +2b+c=0 and ab gt 0` has

A

real roots

B

complex roots

C

exactly one root

D

none of these

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The correct Answer is:
To solve the quadratic equation \( ax^2 + bx + c = 0 \) given the conditions \( 4a + 2b + c = 0 \) and \( ab > 0 \), we will analyze the roots of the equation step by step. ### Step 1: Understand the given conditions We have the quadratic equation: \[ ax^2 + bx + c = 0 \] with the conditions: 1. \( 4a + 2b + c = 0 \) 2. \( ab > 0 \) ### Step 2: Substitute the value of \( c \) From the first condition, we can express \( c \) in terms of \( a \) and \( b \): \[ c = -4a - 2b \] ### Step 3: Rewrite the quadratic equation Substituting \( c \) back into the quadratic equation gives: \[ ax^2 + bx - (4a + 2b) = 0 \] This simplifies to: \[ ax^2 + bx - 4a - 2b = 0 \] ### Step 4: Calculate the discriminant The discriminant \( D \) of a quadratic equation \( ax^2 + bx + c = 0 \) is given by: \[ D = b^2 - 4ac \] Substituting our expression for \( c \): \[ D = b^2 - 4a(-4a - 2b) \] \[ D = b^2 + 16a^2 + 8ab \] ### Step 5: Analyze the discriminant Since \( ab > 0 \), both \( a \) and \( b \) must have the same sign (both positive or both negative). This implies: - \( 16a^2 \) is always positive. - \( 8ab \) is also positive because \( ab > 0 \). Thus, we can conclude that: \[ D = b^2 + 16a^2 + 8ab > 0 \] This means the discriminant is positive. ### Step 6: Determine the nature of the roots Since the discriminant \( D > 0 \), the quadratic equation has two distinct real roots. ### Conclusion The equation \( ax^2 + bx + c = 0 \) has two distinct real roots. ### Final Answer The correct option is that the equation has **two distinct real roots**. ---
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