Write an algebraic expression, in terms of \(x\), for the inverse of function B. [2]
(b) Function C is shown below as a composite function.
Complete the diagram below using two arithmetic operations to show function C as a single function. [4]
Mark scheme (a)
Answer
Marks
Part marks and guidance
\(\frac{x + 3}{5}\) or \(\frac{x}{5} + \frac{3}{5}\) oe
2
B1 for \(x + 3\) written in the correct place on the diagram or in the working space or B1 for answer \(\frac{x}{5} + 3\) oe or \(\frac{x - 3}{5}\) oe or \(5(x + 3)\) oe or correct answer using a different variable
\((x + 3) \div 5\) scores 2 marks \(x + 3 \div 5\) scores 1 marks
Mark scheme (b)
Answer
Marks
Part marks and guidance
\(\times 15\) \(+ 27\)
4
B3 for \(15x\) and +27 or B2 for ×15 or +27 in the correct place or M2 for \(5 \times (3(x + 2))\) [– 3] or better or M1 for \(3(x + 2)\) or better
B3 may be seen on the diagram or as an expression Note: the variable \(x\) can be any letter for the B and M marks
