The augmented matrices of the three systems are given below. \( \left.\begin{array}{rrrr}1 & a & 0 & 4 \\ 1 & 0 & 1 & -2 \\ 0 & 0 & b & 1 \\ 0 & 0 & 0 & 0\end{array}\right] \) where \( a, b \in \mathbb{R} \) with \( b \neq 0 \). How many solutions are there in this case? Infinitely many solutions None of the given options is true given options are correct Exactly one solution No solutions

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

○39.5. а) \( \left\{\begin{array}{l}x-3 y=5, \\ 3 x+2 y=4 ;\end{array}\right. \) б) \( \left\{\begin{array}{l}3 x+y=1, \\ 2 x-5 y=-22 ;\end{array}\right. \) о39.6. а) \( \left\{\begin{array}{l}x+y=4, \\ 4 x-5 y=7 ;\end{array}\right. \) б) \( \left\{\begin{array}{l}x-y=6, \\ 5 x-2 y=-3 ;\end{array}\right. \) о39.7. а) \( \left\{\begin{array}{l}40 x+3 y=-10, \\ 20 x-7 y=-5 ;\end{array}\right. \) б) \( \left\{\begin{array}{l}5 x+2 y=1, \\ 15 x+3 y=3 ;\end{array}\right. \)

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

b. \( x^{2}+2 x=15 \)

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]