For a certain value of the system:
\(3a+4b = 7,\)
\(6a+4b = k-4b\)
has infinitely many solutions (a, b). What is \(k\)?
Simplify the second equation to: \(6a+8 b=k\).
For a system of equations to have infinite solutions, the two equations must be a multiple of each other.
Note that the second equation is twice the first equation.
Can you take it from here?