Foundation January 2021 Paper 1 Q25
25
(a) Simplify \(\;(2x^3y^5)^4\) (2)
(b)
(i) Factorise \(\;x^2 + 5x - 36\) (2)
(ii) Hence, solve \(\;x^2 + 5x - 36 = 0\) (1)
| Scheme | Marks |
|---|---|
| \(16x^{12}y^{20}\) | B2 |
| (2) |
Notes
B2: B1 for an answer in the form \(ax^ny^m\) with 2 correct from \(a = 16\), \(n = 12\), \(m = 20\)
| Scheme | Marks |
|---|---|
| (i) \((x \pm 9)(x \pm 4)\) | M1 |
| \((x + 9)(x - 4)\) | A1 |
| (2) | |
| (ii) Working required Answer: –9, 4 | B1 |
| (1) | |
| (5 marks) |
Notes
M1: for \((x \pm 9)(x \pm 4)\)
or for \((x + a)(x + b)\) where \(ab = -36\) or \(a + b = 5\)
B1: ft from (b)(i)