\(2x^2 – 7x – 4\) factorises as \((2x + 1)(x – 4)\). \((2x + 1)(x – 4) = 0\). \(2x + 1 = 0 \) means \(x = -\frac{1}{2}\). \(x – 4 = 0\) means \(x = 4 ...

As a graph cuts the axis when the y coordinate is zero, then we substitute \(y = 0\) into the quadratic equation and use algebra to solve. We need to factorise the trinomial. When factorised this ...