O-LevelMathematicsAlgebra and graphs4024/22 · May/June 2020 · Q512 Marks

Solve these simultaneous equations. Show your working. 2x-4y = 11, 3x+3y = -6

(a)Solve these simultaneous equations. Show your working. 2x-4y = 11, 3x+3y = -6[4]
(b)Solve the equation 2x² = 3(8-x). Show all your working and give your answers correct to 2 decimal places.[4]
(c)h is inversely proportional to the cube of g. h = 4.5 when g = 2.
(c)(i)Find the formula for h in terms of g.[2]
(c)(ii)Find the value of g when h = 32/3.[2]

Mark scheme

Marking points from the official mark scheme (May/June 2020). The mark or mark type is shown in brackets.

[4] (a) Correct method to eliminate one variable
[4] M2 M1 for attempt to equate coefficients or attempt to make x or y the subject of one equation
[4] x=0.5 oe, y=-2.5 oe
[4] A2 A1 for either x=0.5 oe or y = -2.5 oe
[4] After A0, SC1 for a pair of values that satisfy either equation or for correct answers with no working
[4] (b) 2x²+3x-24 = 0 oe
[4] B1
[4] B2 FT their 3-term quadratic
[4] B1FT for (-3±√(3²-4×2×-24))/(2×2) or for (-3±√p)/(2×2)
[4] 2.79,-4.29
[4] B1
[2] (c)(i) 36/g³
[2] M1 for h = k/g³ oe or [k=] 4.5 × 2³
[2] (c)(ii) 1.5 oe
[2] M1 for g³ = (their 36×3)/32 oe

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