# 10 Deadly Common Algebra Mistakes

Common Patterns of Algebra Mistakes Students often make Common Algebra Mistakes due to confusions such as expand and simplify rules, fractions, indices and equations which that lead the students to the wrong answer. Also these error patterns are very basic and quite easily rectified. Check yourself whether you make similar mistakes, because surprisingly even students […]

Solving radical equations are required to isolate the radicals or surds to one side of the equations. Then square both sides. Here we have two important checkpoints. Checkpoint 1 for Solving radical equations Make sure the whole both sides are to be squared, but not squaring individual terms. This is what I say, (1+2)^2 = […] # Inequality with Variables in the Denominator Solving Inequality with Variables in the Denominator requires special cares due to the direction of the inequalities. Let’s have a look at the following key points. Key Point 1 \begin{aligned} \displaystyle \require{color} \frac{1}{x} &\ge 2 \\ \frac{1}{x} \times x &\ge 2 \times x &\color{green} \text{Many of you may think this is TRUE.} \\ &&\color{green} […] # Inequality Proofs Inequality Proofs can be done many ways. For proving \(A \ge B, one of the easiest ways is to show $$A – B \ge 0$$. Worked Example of Inequality Proofs If $$a, b$$ and $$c$$ are positive real numbers and $$a+b\ge c$$, prove that $$\displaystyle \frac{a}{1+a} + \frac{b}{1+b} \ge \frac{c}{1+c}$$. # Rationalising Denominators Rationalising Denominators simplifies the fractions by multiplying the conjugates of the denominators. Worked Example of Rationalising Denominators Simplify $$\displaystyle\frac{1}{\sqrt{1} + \sqrt{2}} + \frac{1}{\sqrt{2} + \sqrt{3}} + \cdots + \frac{1}{\sqrt{99} + \sqrt{100}}$$. # Absolute Value Inequalities Absolute Value Inequalities are usually proved by the absolute value of a certain value is greater than or equal to it. The square of the value is equal to the square of its absolute value. Proof of Absolute Value Inequalities Prove $$|a| + |b| \ge |a+b|$$. # Inequalities using Arithmetic Mean Geometric Mean Arithmetic Mean of $$a$$ and $$b$$ is always greater than or equal to the Geometric Mean of $$a$$ and $$b$$, for all positive real numbers with with equality if and only if $$a = b$$. This is also called AM-GM (Arithmetic Mean Geometric Mean) inequality. $$\require{color}$$ \begin{aligned} \frac{a + b}{2} \ge \sqrt{ab} \text{ or […]
Nested square roots or nested radical problems are quite interesting to solve. The key skill for this question is to understand how the students can handle “…”. This enables us to setup a quadratic equation to evaluate its exact value using the quadratic formula, $$\require{color}$$ $$x= \frac{-b \ \pm \sqrt{b^2 – 4ac}}{2a}$$. Let’s take a […]