Higher November 2020 Paper 2 Q15
15 Rearrange \(\quad a = \dfrac{b}{c} + 5 \quad\) to make \(c\) the subject. [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| \(ac = b + 5c\) | M1 | oe fraction eliminated |
| \(ac - 5c = b\) or \(c(a - 5) = b\) or \(\dfrac{b}{a - 5}\) | M1dep | oe terms in \(c\) collected |
| \(c = \dfrac{b}{a - 5}\) | A1 | |
| Alternative method 2 | ||
| \(a - 5 = \dfrac{b}{c}\) | M1 | |
| \(\dfrac{1}{a - 5} = \dfrac{c}{b}\) or \(\dfrac{a - 5}{b} = \dfrac{1}{c}\) or \(c(a - 5) = b\) or \(\dfrac{b}{a - 5}\) | M1dep | |
| \(c = \dfrac{b}{a - 5}\) | A1 | |
Additional guidance
| \(c = \dfrac{b}{a - 5}\) in working lines with \(\dfrac{b}{a - 5}\) on answer line | M1M1A1 |