Solve the following equation: bb−5−2b+5=50b2−25

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𝑏

5

2
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+
5
=
50
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2

25
and show your work.

1 answer

To solve the equation

\[ bb - 5 - 2b + 5 = 50b^2 - 25, \]

let's rewrite it clearly. It appears you meant \( b^2 - 2b - 5 = 50b^2 - 25 \). If that's correct, we can solve the equation as follows:

  1. Start with the equation:

\[ b^2 - 2b - 5 = 50b^2 - 25. \]

  1. Move all terms to one side of the equation by subtracting \( 50b^2 \) and adding \( 25 \):

\[ b^2 - 50b^2 - 2b - 5 + 25 = 0. \]

  1. Combine like terms:

\[ -49b^2 - 2b + 20 = 0. \]

  1. Multiply the entire equation by -1 to simplify:

\[ 49b^2 + 2b - 20 = 0. \]

  1. Now, we can use the quadratic formula \( b = \frac{-B \pm \sqrt{B^2 - 4AC}}{2A} \) where \( A = 49, B = 2, C = -20 \).

  2. Calculate the discriminant \( B^2 - 4AC \):

\[ B^2 - 4AC = 2^2 - 4 \cdot 49 \cdot (-20). \]

\[ = 4 + 3920 = 3924. \]

  1. Now, calculate \( \sqrt{3924} \):

Since \( 3924 = 4 \times 981 \) and \( \sqrt{4} = 2 \), we have:

\[ \sqrt{3924} = 2\sqrt{981}. \]

Since \( 981 = 3^2 \times 109 \), rewrite it:

\[ \sqrt{981} = 3\sqrt{109}. \]

So

\[ \sqrt{3924} = 2 \times 3\sqrt{109} = 6\sqrt{109}. \]

  1. Substitute back into the quadratic formula:

\[ b = \frac{-2 \pm 6\sqrt{109}}{2 \times 49} = \frac{-2 \pm 6\sqrt{109}}{98} = \frac{-1 \pm 3\sqrt{109}}{49}. \]

  1. Thus, the two solutions for \( b \) are:

\[ b = \frac{-1 + 3\sqrt{109}}{49} \quad \text{and} \quad b = \frac{-1 - 3\sqrt{109}}{49}. \]

These are the solutions to the given equation.