Mathematics · Oct / Nov 2021 · Paper 22 · Question 18
0580
As printed in the paper
The question as text
Solve the simultaneous equations. You must show all your working. y x x y x 9 21 2 3 2 = - + = - x = y = x = y = [5]
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x² – 11x + 24 [= 0] or y² – 16y + 39 [= 0] (x – 8)(x – 3) [= 0] or (y – 13)(y – 3) [= 0] [x =] 3 [y =] 3 [x =] 8 [y =] 13 [7]
M2 M1 for x² – 9x + 21 = 2x – 3 oe 2 y + 3 y + 3 or y = − 9 + 21 oe 2 2 M1 or for correct factors for their quadratic equation or for correct use of quadratic formula for their equation
B2 B1 for one correct pair or two correct x values or two correct y values. If B0 scored and at least 2 method marks scored
SC1 for correct substitution of both of their x values or their y values into y = x2 – 9x + 21 or y = 2x – 3
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