Exponents & Surds
We extend Grade 10 exponent work to include equations with rational exponents and surds, and apply surd rationalization in more complex algebraic contexts.
1.1 Rational Exponents & Equations with Surds
- Simplify and solve equations with rational exponents
- Solve equations involving surds (checking for extraneous roots)
- Apply exponential laws to simplify complex expressions
Real-World Connection
Equations with surds appear in structural engineering: the deflection of a beam involves square roots of variables. An extraneous solution would mean choosing a beam that collapses โ so checking every answer is not optional.
Property / Rule
Solving Exponential Equations
Write both sides with the same base, then equate exponents. If bases cannot be matched directly, use logarithms (introduced later).
Property / Rule
Solving Surd Equations
Isolate the surd, then square both sides to eliminate the radical. ALWAYS substitute back to check for extraneous roots (introduced by squaring).
โ ๏ธ Warning
Squaring both sides can introduce extraneous (false) solutions. For example, squaring gives , but . ALWAYS substitute back.
Worked Example
Exponential equation
Problem
Worked Example
Surd equation
Problem
CAPS Cognitive Level Distribution