0580/42 Oct/Nov 2024, Question 3: Simultaneous Equations with a Curve
Cambridge IGCSE Mathematics 0580 · Paper 42 (Extended) · Calculator · 17 marks
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The question, in short
Simplify three algebraic expressions, use an isosceles triangle's perimeter to find a, solve a quadratic with the formula, and solve simultaneous equations.
Summarised in our own words. Use the official paper for the exact wording and the diagram.
Part (ai) · 2 marks
Simplify 3m − 5n − 4m + 8n by collecting like terms.
- 13m − 4m = −m and −5n + 8n = 3n
- 2= −m + 3n
Answer−m + 3n
Part (aii) · 2 marks
Simplify (3a²c³)⁴, applying the power to each factor.
- 13⁴ = 81, (a²)⁴ = a⁸, (c³)⁴ = c¹²
- 2= 81a⁸c¹²
Answer81a⁸c¹²
Part (aiii) · 2 marks
Simplify 4x/5 − 3x/10 + 2x/15 by combining the fractions.
- 1Use the common denominator 30.
- 24x/5 = 24x/30, 3x/10 = 9x/30, 2x/15 = 4x/30
- 3(24x − 9x + 4x)/30 = 19x/30
Answer19x/30
Part (b) · 3 marks
An isosceles triangle has perimeter 35.5 cm, equal sides (3a + 2) cm and base a cm. Find a.
- 1a + 2(3a + 2) = 35.5
- 27a + 4 = 35.5
- 37a = 31.5
- 4a = 4.5
Answer4.5
Part (c) · 3 marks
Solve 5x² − 4x − 3 = 0 using the quadratic formula, showing all working.
- 1x = (−(−4) ± √((−4)² − 4 × 5 × (−3)))/(2 × 5)
- 2x = (4 ± √76)/10
- 3x = −0.4718… ≈ −0.472 and x = 1.2718… ≈ 1.27
Answer−0.472 or −0.4718 to −0.4717 and 1.27 or 1.271 to 1.272
Part (d) · 5 marks
Solve the simultaneous equations y = x² − 4x + 5 and y = 2x − 3, showing all working.
- 1x² − 4x + 5 = 2x − 3
- 2x² − 6x + 8 = 0
- 3(x − 2)(x − 4) = 0, so x = 2 or x = 4
- 4y = 2(2) − 3 = 1 and y = 2(4) − 3 = 5
- 5x = 2, y = 1 and x = 4, y = 5
Answerx = 2, y = 1 and x = 4, y = 5
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Also searched as: 0580/42/O/N/24 · 0580_w24_qp_42 · 0580 w24 42 · question 3.
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