31. Equations in one variable and word problems

 

31. Equations in one variable and word problems

Learn and Remember :

 1. An equation is an equality with variables in it.

 2. An equation with one variable having the highest power 1, is called a simple equation.

e.g. x+5= 7 is a simple equation.

3. That value of the variable which makes the left hand side of an equation equal to the right hand side, is said to satisfy the equation.

e.g. consider the equation x +5 = 7.

X= 2 satisfies this equation.

2 is called the ‘solution' or the root of the equation x +5=7. “Solving an equation' means determining its solution.

4. If the same number is added to or subtracted from the left hand side (LHS) and the right hand side (RHS) of an equation, the equation remains unaltered.

5. If the LHS and the RHS of an equation are multiplied or divided by the same non-zero number, then the equation remains unaltered.

 6. For solving a word problem, first suppose a variable for the unknown quantity. Then frame an equation using the information in the problem. Solve the equation using the properties of equality.