Answer:
D -26
Step-by-step explanation:
A: 8
[tex]y = f(g(x)) = ( \sqrt{7x + b)} \\ y= \sqrt{7x + b} \\ at \: (4 \: \: 6) \\ \\ i.e. \: plugging \: x = 4 \: and \: y = 6 \\ \\ 6 = \sqrt{7 \times 4 + b} \\ 36 = 28 + b \\ b = 36 - 28 \\ b = 8 \\ [/tex]
