Paper 2 · November 2013 (topical set) · Algebra and Equations
The lines x = 20 and x = 2y are drawn on the same axes. Calculate the coordinates of the point where they cross.
Model answer
(20; 10)
Also accepted: 20; 10
Explanation
Every point on the line x = 20 has x = 20. Substituting into x = 2y gives 20 = 2y, so y = 10. The two lines cross at (20; 10), which is one corner of the region defined by x + y <= 100, x > 20, x <= 2y and x > y.
ZIMSEC Mathematics 4008/2, November 2013, Q12(d), via the Topical Collection