Higher November 2020 Paper 1 Q7
7
(a) Solve \(5(4 - x) = 7 - 3x\)
Show clear algebraic working. (3)
Show clear algebraic working. (3)
(b) Factorise fully \(16m^3g^3 + 24m^2g^5\) (2)
(c)
(i) Factorise \(y^2 - 2y - 48\) (2)
(ii) Hence, solve \(y^2 - 2y - 48 = 0\) (1)
| Scheme | Marks |
|---|---|
| \(20 - 5x\;(= 7 - 3x)\) | M1 |
| E.g. \(20 - 7 = -3x + 5x\) or \(-5x + 3x = 7 - 20\) | M1 |
| Working required Answer: 6.5 oe | A1 |
| (3) |
Notes
M1: for expansion of bracket
M1: ft from a 4-term equation
for a correct process of isolating terms in \(x\) on one side of the equation and numbers on the other side
A1: dep on M1 awarded and from correct working
| Scheme | Marks |
|---|---|
| M1 | |
| Correct answer scores full marks (unless from obvious incorrect working) Answer: \(8m^2g^3(2m + 3g^2)\) | A1 |
| (2) |
Notes
M1: for any correct partial factorisation with at least 2 factors, one of which must be a letter or the correct common factor with no more than 1 error inside the bracket
| Scheme | Marks |
|---|---|
| (i) \((y \pm 6)(y \pm 8)\) | M1 |
| Correct answer scores full marks (unless from obvious incorrect working) Answer: \((y - 8)(y + 6)\) | A1 |
| (ii) Answer: 8, \(-6\) | B1 |
| (3) | |
| (8 marks) |
Notes
B1: must ft from their factors in (c)(i)