B1 n (2n) This mark is for combining terms inside bracket correctly 2 B1 1n2 is OK n2 18 (x2 + 2x 3) (x2 + x 3) M1 Or attempt to – – – ‘balance’ equations y = x A1 2.3 and 1.3 A1 ft ft if M awarded and their line drawn – Q Answer Mark Comments 19(a) B1 is essential seen or implied √3 √3  3 3 = 9 and = 3 or √3 √3   Accept (31.5)2 = 33 = 27 oe 3 3 = 3  19(b) M1 Invisible brackets must be recovered for M1 (= 27 18) (3√3)2 – (3√2)2 – or + AD2 = (3√2)2 (3√3)2 or 3 A1 √9 + (= M1Dep Dep on M1, not on A1 as well 3√2 √2 4√2) 0.5 their base their 3 M1Dep   A1 6√2
n (2n) 2 B1 This mark is for combining terms inside bracket correctly n2 B1 1n2 is OK 18 (x2 + 2x – 3) – (x2 + x – 3) M1 Or attempt to ‘balance’ equations y = x A1 – 2.3 and 1.3 A1 ft ft if M awarded and their line drawn Q Answer Mark Comments 19(a) 3  3 = 9 and √3  √3 = 3 or 3  3 = 3 B1 √3  √3 is essential seen or implied Accept (31.5)2 = 33 = 27 oe 19(b) (3√3)2 – (3√2)2 (= 27 – 18) or (3√2)2 + AD2 = (3√3)2 M1 Invisible brackets must be recovered for M1 √9 or 3 A1 3√2 + √2 (= 4√2) M1Dep Dep on M1, not on A1 as well 0.5  their base  their 3 M1Dep 6√2 A1