Drawing & Using Graphs: WJEC GCSE Foundation June 2018 Unit 1 Q12

Foundation June 2018 Unit 1 Q12

WJECFoundationCurrent spec6 marksDrawing & Using Graphs

12. The table below shows some values of \(y = x - 3\) for values of \(x\) from \(-4\) to 6.

\(x\)	\(-4\)	\(-2\)	\(0\)	\(2\)	\(4\)	\(6\)
\(y = x - 3\)	\(-7\)		\(-3\)			\(3\)

(a) Complete the table above. [2]

(b) On the graph paper below, draw the graph of the straight line \(y = x - 3\) for values of \(x\) from \(-4\) to 6 only. [2]

Graph paper with x-axis from -4 to 6 (grid from about -5 to 7) and y-axis from -8 to 4, labelled every 2 units

(c) The straight line you have drawn on the graph for values of \(x\) from \(-4\) to 6 is a diagonal of a square.

Write down the coordinates of the four corners of this square. [2]

( ……… , ……… ) ( ……… , ……… ) ( ……… , ……… ) ( ……… , ……… )

Mark scheme (a)

Scheme	Marks	Comments
−5 −1 1	B2	B2 for all three correct. B1 for one or two correct.

Mark scheme (b)

Scheme	Marks	Comments
Correct plots.	P1	FT ‘their y-values at x = −2, 2 and 4’. 2 correct plots sufficient as they are told it’s a straight line. Allow ±’½ a small square’. P0 if any incorrect plot.
Straight line from (−4,−7) to (6,3)	L1	CAO no FT. Allow ±’1 small square’. Must be from (−4,−7) to (6,3) but allow ‘extended’ line. A correct line gains P1L1.

Mark scheme (c)

Scheme	Marks	Comments
(−4,−7) (6,−7) (6,3) (−4,3) (In any order)	B2	B2 for all four correct. B1 for three correct. Only award B1 (not B2) if all four correct coordinates given for their extended line. If L0 from a ‘shortened correct line’ then FT (for B2 or B1). If L0 from an incorrect line then FT (for B2 or B1) only if a quadrilateral has been drawn using ‘their line’ as a diagonal. SC1 for the correct square drawn but no (or incorrect) coordinates given.