Answer:
21
Explanation:
Equation of the given line y = 15x + b.
Points passing through the above line (6.4, 117) and (6.6, 120)
If these point pass through the given line.
These point should satisfy the equation.
plugging in value of one of the point (6.4, 117) in the line y = 15x + b
we have
117 = 15*6.4 + b
=> 117 = 96 + b
=> 117 - 96 = b
=> b = 21
Thus, value of b in the given equation is 21.