Verify that a=x−273\displaystyle a = \frac{x - 27}{3}a=3x−27 is the subject of x=3(a+9)x = 3(a + 9)x=3(a+9)
210 exam-style questions on Eduqas GCSE Maths Changing the Subject of a Formula. Each one has a worked solution and a mark scheme showing where the marks go.