Algebraic Formulae

3.1  Algebraic Formulae
 
  Definition  
     
 

It is written in the form of an equation that combines an algebraic expression using addition, subtraction, multiplication or division.

 
 
Forming formula
 
Example
   
1.  \(y= 3x -5\)
   
2.  \(w = \dfrac{6-v}{v}\)
   
3. \(L = \dfrac{1}{2} th\)
   
4.  \(A = \pi r^2\)
   
Changing the subject of the formula
 
Tips
  • The subject of the formula is represented by a letter.
  • The subject of the formula should be on the left side of the equation. 
 
Example

Determining the value of the variable
 
Tips

The value of a variable in the subject of the formula can be obtained when the value of other variables is given.

 
Example
 

Given \(Q= \dfrac{2v}{-v +u}\), calculate the value of \(u\), where \(v=2, Q= 4\).

\(\begin{aligned} \\\space4 &= \dfrac{2(2)}{-2 + u} \\\\ 4 (-2 +u) &= 4 \\\\ -8 + 4u &= 4 \\\\ 4u &= 12 \\\\ u &= \dfrac{12}{4} \\\\ u &=3. \end{aligned}\)

   
Solving problems
 
Tips

It involves changing the subject of a formula, a combination of basic mathematical operations, square and square root.

Algebraic Formulae

3.1  Algebraic Formulae
 
  Definition  
     
 

It is written in the form of an equation that combines an algebraic expression using addition, subtraction, multiplication or division.

 
 
Forming formula
 
Example
   
1.  \(y= 3x -5\)
   
2.  \(w = \dfrac{6-v}{v}\)
   
3. \(L = \dfrac{1}{2} th\)
   
4.  \(A = \pi r^2\)
   
Changing the subject of the formula
 
Tips
  • The subject of the formula is represented by a letter.
  • The subject of the formula should be on the left side of the equation. 
 
Example

Determining the value of the variable
 
Tips

The value of a variable in the subject of the formula can be obtained when the value of other variables is given.

 
Example
 

Given \(Q= \dfrac{2v}{-v +u}\), calculate the value of \(u\), where \(v=2, Q= 4\).

\(\begin{aligned} \\\space4 &= \dfrac{2(2)}{-2 + u} \\\\ 4 (-2 +u) &= 4 \\\\ -8 + 4u &= 4 \\\\ 4u &= 12 \\\\ u &= \dfrac{12}{4} \\\\ u &=3. \end{aligned}\)

   
Solving problems
 
Tips

It involves changing the subject of a formula, a combination of basic mathematical operations, square and square root.