Higher January 2023 Paper 2 Q13
13 Solve \(\;\dfrac{x + 3}{4} - \dfrac{7 - x}{5} = 4.3\)
Show clear algebraic working.
(3)
| Scheme | Marks |
|---|---|
eg \(20 \times \dfrac{x + 3}{4} - 20 \times \dfrac{7 - x}{5} = 20 \times 4.3\) or eg \(5(x + 3) - 4(7 - x) = 20 \times 4.3\) or eg \(\dfrac{5(x + 3)}{20} - \dfrac{4(7 - x)}{20}\;(= 4.3)\) or eg \(\dfrac{5(x + 3) - 4(7 - x)}{20}\;(= 4.3)\) | M1 |
| eg \(5x + 15 - 28 + 4x = 4.3 \times 20\) oe eg \(9x - 13 = 86\) eg \(9x = 99\) | M1 |
| Working required Answer: 11 | A1 |
| (3) | |
| (3 marks) |
Notes
M1: For clear intention to multiply all terms by 20 (or 4 × 5) or a multiple of 20 oe
or
to express LHS as two fractions over 20 (or 4 × 5) or a multiple of 20 oe or as a single fraction with a denominator of 20 (or 4 × 5) or a multiple of 20 oe
if expanded numerator, allow one error
M1: Expanding brackets and multiplying by denominator with no more than one error in total from multiplying out brackets
[we must see 4.3 × 20 or 86 accurately]
A1: dep on M1