(b) Write down the inequality represented by the number line.
[2 marks]
Mark scheme (a)
Answer
Mark
Comments
\(5x - 3x\) or \(2x\) or \(3x - 5x\) or \(-2x\) or \(15 - 6\) or 9 or \(6 - 15\) or \(-9\)
M1
may be seen as an annotation to the given inequality eg \(-6\) written under \(+15\)
\(2x \gt 9\) or \(-9 \gt -2x\) or 4.5 or \(\dfrac{9}{2}\) or \(4\dfrac{1}{2}\)
A1
implied by correct answer
\(x \gt 4.5\) or \(x \gt \dfrac{9}{2}\) or \(x \gt 4\dfrac{1}{2}\)
A1ft
ft solution of inequality of the form \(2x \gt k\) where \(k\) is a number or \(m \gt -2x\) where \(m\) is a number or \(ax \gt 9\) where \(a\) is an integer not equal to 1 or \(-9 \gt bx\) where \(b\) is an integer not equal to 1
Additional guidance
In all cases accept the inequality written correctly in reverse order For example, for \(2x \gt 9\) accept \(9 \lt 2x\)
\(4.5 \lt x\)
M1A1A1
\(2x \gt 21,\ x \gt 10.5\)
M1A0A1ft
\(8x \gt 9,\ x \gt 1.125\)
M1A0A1ft
Do not allow a correct answer in working followed by an incorrect answer on the answer line
eg \(x \gt \dfrac{9}{2}\) in working with 4.5 on the answer line
M1A1A0
Do not allow the correct answer with another answer
eg \(x \gt 4.5\) and \(x = 4.5\) on the answer line
M1A1A0
Mark scheme (b)
Answer
Mark
Comments
\(2 \leqslant x \lt 5\) or \(5 \gt x \geqslant 2\)
B2
any letter B1 \(2 \leqslant x\) or \(x \geqslant 2\) or \(x \lt 5\) or \(5 \gt x\) SC1 \(2 \lt x \leqslant 5\) or \(5 \geqslant x \gt 2\)
