15 (a) 8, 11, 16 2 M1 substitutes 1, 2 or 3 into + 7 n2 A1 cao (b) 11th 1 B1 for 11th or 11 16 125, 250, 100, 3 M1 for ÷20 × 50 oe or 50 ÷ 20 (= 2.5) 125, 5 A1 for 2 or 3 correct A1 cao 17 (a) 2y3 1 B1 cao (b) + 1) 1 B1 cao m(m (c) 2 M1 subtracts 5 from both sides or divides each term by 3 as a first step A1 oe with the subject h
15 (a) 8, 11, 16 2 M1 substitutes 1, 2 or 3 into n2 + 7 A1 cao (b) 11th 1 B1 for 11th or 11 16 125, 250, 100, 125, 5 3 M1 for ÷20 × 50 oe or 50 ÷ 20 (= 2.5) A1 for 2 or 3 correct A1 cao 17 (a) 2y3 1 B1 cao (b) m(m + 1) 1 B1 cao (c) 2 M1 subtracts 5 from both sides or divides each term by 3 as a first step A1 oe with h the subject