Mathematics · Oct / Nov 2021 · Paper 41 · Question 8

1.6 oe [2]

M1 for 3 – 5x = – 5

3 − x oe final answer 5 [2]

M1 for x = 3 – 5y or y 3 = − x or better, 5 5 or y – 3 = – 5x oe

2 20.25 − ( 1.5 + x ) [3]

Method 1 2

B1 for ( ± ± ) 1.5 x seen

B1 for [b =] 18 + their 1.52 OR Method 2 2 2

B1 for b − a − 2 ax − x or for b = 20.25

B1 for a = 1.5

Correct sketch with max in correct quadrant at ( − 1.5, 20.25 ) [3]

FT their 2 20.25 − ( their 1.5 + x ) provided in that form

B1 for ∩shape or for ∪shape if in form 2 c ( + d + x ) in part (b)(i)

B1 for TP at ( − 1.5, k ) or ( k , 20.25 ) FT 2 their 20.25 ± ( their 1 .5 + x ) or for (–1.5, 20.25) seen

[y =] 34 – 11x [6]

B2 for –3 – 2x

or B1 for either kx –3, k ≠ 0 or –2x + n or for 18 – 3 – 2x M1dep for gradient = their (–3 – 2(4) )

B1 for y-value at x = 4, is –10 M1dep for their –10 = (their –11)4 + c oe