Formulas and rules
Every key math formula and rule, organised by topic and school level, with examples and study tips.
Algebra 5
Algebraic notation
2x means 2 times x. x^2 means x squared. Like terms can be collected.
Expanding brackets
a(b + c) = ab + ac
Multiply the term outside by every term inside.
Factorising
ab + ac = a(b + c)
Take the highest common factor outside the brackets.
Solving linear equations
ax + b = c -> x = (c - b) / a
Do the same operation to both sides to keep the balance and isolate x.
Sequences
arithmetic: u_n = a + (n-1)d ; geometric: u_n = a x r^(n-1)
Arithmetic sequences add a constant, geometric ones multiply by a constant.