Answer:
12x -y = 24
Explanation:
You want a line through points (4, f(4)) and (6, f(6)). Evaluating the function, we find the points are (4, 24) and (6, 48). In the 2-point form of the equation for a line, we find ...
y = (y2 -y1)/(x2 -x1)(x -x1) + y1
y = (48 -24)/(6 -4)(x -4) +24 . . . . filling in the values
y = 12(x -4) +24 . . . . . . one form of the equation for the secant
12x -y = 24 . . . . . . . . . . standard form equation of the line
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The slope-intercept form of the equation is ...
y = 12x -24