Find the range of values of \(m\) for which the straight line \(y=mx-5\) intersects the curve \(y=x^2-1\) in two distinct points.
The line meets the curve where
\[ mx-5=x^2-1,\]
which rearranges to
\[x^2-mx+4 = 0.\]
This has two distinct roots if the discriminant \(m^2 -16\) is positive, that is if \(m < -4\) or \(m > 4\).
This can be written as \(\big|m\big|>4\), using the modulus function.
