Understand How to Solve Equations with Two Unknowns

This activity includes different questions that have equations with two unknowns.

 

The two letters in each equation stand for two numbers. Note: these numbers could be different or the same.

 

Example

 

3x - 2y = 2

 

Which of the solutions satisfy the equation?

 

x =  2    y = 2

x = 8    y = 4

x = 4    y = 5

x = 10    y = 2

 

As you have been given options, put each pair into the equation to see if it can give the equation

3x - 2y = 2

 

Remember to carry out any calculation in brackets first.

 

x = 2    y = 2   

fits because (3 x 2) - (2 x 2) = 6 - 4 = 2

 

x = 8    y = 4   

does not fit because

(3 x 8) - (2 x 4) = 24 - 8 = 16

 

x = 4    y = 5   

fits because (3 x 4) - (2 x 5) = 12 - 10 = 2

 

x = 10    y = 2

does not fit because

(3 x 10) - (2 x 2) = 30 - 4 = 26

 

Remember to use a sensible process of trial and error when solving equations with two unknowns.

 

Let's start the questions now.