Given the quadratic 5x^2 + ax - 1 = 0, what would a need to be in order for the discriminate to be 29?

Question

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Answer 1

The discriminant of a quadratic function is the value of the square root portion of the quadratic formula: b²-4ac where a is the coefficient for x², b is the coefficient for x, and c is the constant. Once you plug in for these values and set equal to 29 then you have an equation you can solve for a.

Answer 2

The discriminant of Ax² + Bx + C is B² - 4AC.

So, a² - 4(5)(-1) = 29.

a² = 9

a = ±3

Answer 3

Hey Kyla!

In this problem, we are trying to find what the value of "a" would have to be for the discriminant to be 29. The discriminant is the part of the quadratic equation under the square root sign, or b^2 - 4ac, so let's gather what we have and set it equal to 29:

b^2 - 4ac = 29

a^2 - 4(5)(-1) = 29

a^2 = 9

a = ±3

Therefore our "a" value would be 3