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The graph of the function y=16x^(2)+8(a+...

The graph of the function `y=16x^(2)+8(a+2)x-3a-2` is strictly above the x - axis, then number of integral velues of 'a' is

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To solve the problem, we need to determine the number of integral values of \( a \) such that the quadratic function \( y = 16x^2 + 8(a + 2)x - (3a + 2) \) is strictly above the x-axis. This means that the discriminant of the quadratic must be less than zero. ### Step-by-Step Solution: 1. **Identify the coefficients**: The given quadratic function is in the form \( y = ax^2 + bx + c \). - Here, \( a = 16 \) - \( b = 8(a + 2) \) - \( c = -(3a + 2) \) 2. **Calculate the discriminant**: The discriminant \( D \) of a quadratic equation \( ax^2 + bx + c \) is given by: \[ D = b^2 - 4ac \] Substituting the values: \[ D = [8(a + 2)]^2 - 4 \cdot 16 \cdot (-(3a + 2)) \] 3. **Simplify the discriminant**: \[ D = 64(a + 2)^2 + 64(3a + 2) \] Factor out 64: \[ D = 64\left[(a + 2)^2 + (3a + 2)\right] \] 4. **Expand and combine like terms**: \[ D = 64\left[a^2 + 4a + 4 + 3a + 2\right] \] \[ D = 64\left[a^2 + 7a + 6\right] \] 5. **Set the discriminant less than zero**: For the quadratic to be strictly above the x-axis, we need: \[ D < 0 \implies a^2 + 7a + 6 < 0 \] 6. **Factor the quadratic**: \[ a^2 + 7a + 6 = (a + 6)(a + 1) \] 7. **Determine the intervals**: The quadratic \( (a + 6)(a + 1) < 0 \) is negative between its roots: - The roots are \( a = -6 \) and \( a = -1 \). - The inequality holds for \( -6 < a < -1 \). 8. **Identify integral values**: The integral values of \( a \) in the interval \( (-6, -1) \) are: - \( -5, -4, -3, -2 \) 9. **Count the integral values**: There are 4 integral values: \( -5, -4, -3, -2 \). ### Final Answer: The number of integral values of \( a \) is **4**.
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