Learning Resources

Functions of Two Variables

Answers to Activities Questions

1. (a) A = xy

(b) (i) A = x(50 - x) or A = 50x - x² , (ii) A = (50 - y)(y) or A = 50y - y²

2 (a) A = x(3y) or A = 3xy

(b)(i) A = 3xy = 3x(40 - x) or A = 120x - 2x²
(ii) A = 3xy = 3(60 - 1.5)y or A = 180y - 4.5y²

3. A box has a rectangular base, x metres wide and 2x metres long, and a height of y metres:
(a) S = 4x² + 6xy
(b)(i) S = or S =
(ii) S = or S =

4. (a) S = 2pr² +2prh

(b) (i) S = or S =
(ii) S = or S =

5. (a) A = 2xy

(b) A =

6. (a) A = 3xy

(b) (i) A = 3x(10 - x²) or A = 30x - 3x³

(ii) A =