Edexcel C1 2017 June — Question 9

Exam BoardEdexcel
ModuleC1 (Core Mathematics 1)
Year2017
SessionJune
TopicSimultaneous equations

9. (a) On separate axes sketch the graphs of
  1. \(y = - 3 x + c\), where \(c\) is a positive constant,
  2. \(y = \frac { 1 } { x } + 5\) On each sketch show the coordinates of any point at which the graph crosses the \(y\)-axis and the equation of any horizontal asymptote. Given that \(y = - 3 x + c\), where \(c\) is a positive constant, meets the curve \(y = \frac { 1 } { x } + 5\) at two distinct points,
    (b) show that \(( 5 - c ) ^ { 2 } > 12\)
    (c) Hence find the range of possible values for \(c\).