O-LevelMathematicsAlgebra and graphs4024/21 · May/June 2017 · Q79 Marks
Factorise completely 12a²b - 15ab³ .
- (a)Factorise completely 12a²b - 15ab³ .[1]
- (b)(i)Write 4x² + 12x + 9 in the form (cx + d)².[1]
- (b)(ii)Hence solve 4x² + 12x + 9 = 49.[2]
- (c)Express as a single fraction in its simplest form (p+1)/2 - (p-3)/4[3]
- (d)Solve 2(3m + 4) < 3 .[2]
Mark scheme
Marking points from the official mark scheme (May/June 2017). The mark or mark type is shown in brackets.
- [1] 3ab(4a - 5b²)
- [1] (2x + 3)² isw
- [2] 2, -5
- [1] M1 for 2x + 3 = (±)√49 soi
- [3] (p+5)/4 final answer
- [2] M2 for (4p+4-2p+6)/8 or (2p+2-p+3)/4 soi
- [1] M1 for (4(p+1)-2(p-3))/2x4 or (2(p+1)-(p-3))/4
- After 0, SC1 for answer (p-1)/4 or 2p + 10 or p+5
- [2] m < -5/6 m < -0.833[...] final answer
- [1] M1 for 6m + 8 < 3 or 3m + 4 < 3/2
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