Higher June 2017 Paper 3 Q14
14
(a) Simplify \(\dfrac{x^2 - 16}{2x^2 - 5x - 12}\) (3)
(b) Make \(v\) the subject of the formula \(w = \dfrac{15(t - 2v)}{v}\) (3)
| Answer | Mark | Notes |
|---|---|---|
| \(\dfrac{x + 4}{2x + 3}\) | M1 | Factorising the denominator \((2x \pm 3)(x \pm 4)\) or \(2\left(x \pm 1\tfrac{1}{2}\right)(x \pm 4)\) |
| M1 | Factorising the numerator \((x - 4)(x + 4)\) | |
| A1 | oe |
| Answer | Mark | Notes |
|---|---|---|
| \(v = \dfrac{15t}{w + 30}\) | M1 | A correct step towards solution e.g. expanding brackets to get \(15t - 30v\) or multiply both sides by \(v\) |
| M1 | For a method to rearrange the formula to isolate terms in \(v\) eg \(vw + 30v = 15t\) | |
| A1 | oe |