Covers Lessons 1–7: Variables, expressions, substitution, like terms and algebraic operations.
Question 9 3 marks
If $x = 3$ and $y = 5$, evaluate:
(a) $2x + y$ 1 mark
(b) $xy - 4$ 1 mark
(c) $x^2 + 2y$ 1 mark
(a) $2(3) + 5 = 6 + 5 = 11$ [1]
(b) $(3)(5) - 4 = 15 - 4 = 11$ [1]
(c) $3^2 + 2(5) = 9 + 10 = 19$ [1]
Question 10 3 marks
(a) Simplify $3x + 2y + 5x - y$. 2 marks
(b) Simplify $4a \times 3b$. 1 mark
(a) $3x + 5x = 8x$ [1]. $2y - y = y$ [1]. Answer: $8x + y$
(b) $4a \times 3b = 12ab$ [1]
Question 11 4 marks
(a) Write an expression for "5 more than twice a number $n$". 1 mark
(b) If the number is 7, what is the value of your expression? 1 mark
(c) Simplify $6x^2 \div 2x$. 2 marks
(a) $2n + 5$ [1]
(b) $2(7) + 5 = 14 + 5 = 19$ [1]
(c) $6x^2 \div 2x = \frac{6x^2}{2x} = 3x$ [2]