There are no numbers on the graph, so we cannot tell for sure the value of f(3).
If the grid squares are each one unit, then the graph of f(x) appears to go through the grid point (3, -1). This means f(3) = -1.
Using this value in the expression for g(x), we have
.. g(3) = -4*f(3) +7
.. g(3) = -4*(-1) +7
.. = 4 +7
.. = 11
The value of g(3) is 11.
