Solve for b 4x^2+bx+25=0

$4 x^{2} + b x + 25 = 0$

Move all terms not containing $b$ to the right side of the equation.

Subtract $4 x^{2}$ from both sides of the equation.

$b x + 25 = - 4 x^{2}$

Subtract $25$ from both sides of the equation.

$b x = - 4 x^{2} - 25$

Divide each term in $b x = - 4 x^{2} - 25$ by $x$ and simplify.

Divide each term in $b x = - 4 x^{2} - 25$ by $x$ .

$\frac{b x}{x} = \frac{- 4 x^{2}}{x} + \frac{- 25}{x}$

Simplify the left side.

Cancel the common factor of $x$ .

Cancel the common factor.

$\frac{b x}{x} = \frac{- 4 x^{2}}{x} + \frac{- 25}{x}$

Divide $b$ by $1$ .

$b = \frac{- 4 x^{2}}{x} + \frac{- 25}{x}$

Simplify the right side.

Simplify each term.

Cancel the common factor of $x^{2}$ and $x$ .

Factor $x$ out of $- 4 x^{2}$ .

$b = \frac{x (- 4 x)}{x} + \frac{- 25}{x}$

Cancel the common factors.

Raise $x$ to the power of $1$ .

$b = \frac{x (- 4 x)}{x^{1}} + \frac{- 25}{x}$

Factor $x$ out of $x^{1}$ .

$b = \frac{x (- 4 x)}{x \cdot 1} + \frac{- 25}{x}$

Cancel the common factor.

$b = \frac{x (- 4 x)}{x \cdot 1} + \frac{- 25}{x}$

Rewrite the expression.

$b = \frac{- 4 x}{1} + \frac{- 25}{x}$

Divide $- 4 x$ by $1$ .

$b = - 4 x + \frac{- 25}{x}$

Move the negative in front of the fraction.

$b = - 4 x - \frac{25}{x}$