Mathematics · Oct / Nov 2025 · Paper 22 · Question 20
0580
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( )x x 2 1 21 f Á , x 2 1 ¼ ( )x x 3 4 g È
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20(a)(i)[1]
10 [1]
20(a)(ii)[2]
–17 [1]
M1 for g(–7) oe 2 + 21 or 3 4 oe soi − 2 1 x
20(a)(iii)[3]
21 + x or 21 1 x + oe final answer 2 x 2 2 [3]
M2 for one step from answer + y e.g. x = 21 or x = 21 1 + 2 y 2 y 2 21 = + or 2 y 1 x + 21 x = or 2xy = 21 + x or 2 y x
or M1 for correct first step e.g. 21 x = or better − 2 y 1 or y (2x – 1) = 21 or better
20(b)[5]
5 5 − 3 and oe 2 [5]
B3 for 6x2 + 5x – 25 [= 0]
or M1 for 21 = (2x – 1)(3x + 4) oe
B1 for 6x2 – 3x + 8x – 4 or better and
M1 for correct method to solve their three-term quadratic e.g. (3x – 5)(2x + 5) [= 0] −± −××− 5 5 4 6 25 2 or oe 12
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