Question

Solve the following pair of equations by substitution method: 7x – 15y = 2 and x + 2y = 3 

Answer 1

7x – 15y = 2   .......(1)

x + 2y = 3   ..........(2)

Step 1: We pick either of the equations and write one variable in terms of the other. Let us consider the Equation (2) :

x + 2y = 3

and write it as x = 3 – 2y   .......(3)

Step 2 : Substitute the value of x in Equation (1). We get

7(3 – 2y) – 15y = 2

i.e., 21 – 14y – 15y = 2

i.e., – 29y = –19

Therefore, y =19/29

Step 3 : Substituting this value of y in Equation (3), we get