Find the slope and \( y \)-intercept of the graph of the equation. \[ y=\frac{2}{5} x-1 \] Slope \( =\square \) (Enter a fully reduced fraction.) The y-intercept is \( \square \). (Simplify your answer. Type an ordered pair.)

a. \( x^{2}=49 \)

d. \( 2 x^{2}+27=-21 x \)

Write an equation that expresses the following relationship. \( w \) varies directly with the cube of \( u \) and inversely with \( d \) In your equation, use \( k \) as the constant of proportionality,

Write an equation that expresses the following relationship. \( p \) varies jointly. with \( d \) and the square root of \( u \) In your equation, use \( k \) as the constant of proportionality. \( \square=\square \quad \frac{\square}{\square} \)

Write an equation that expresses the following relationship. \( u \) varies directly with \( p \) and inversely with \( d \) In your equation, use \( k \) as the constant of proportionality. पा]