Question

Solve following pair of linear equations in two variables using substitution method: 2x + 5y = 30 and 2x - y = 6

Answer 1

Answer:

2x+5y=30 ... (I)

2x-y=6 ... (ii)

let's us look closely at the given equations and, we'll find that both the equations have 2x is common , so we will find the value of 2x from equation (I) and substitute in it equation (ii) and solve for the value of x

from equation (I)

2x+5y=30

2x=30-5y

Substituting 2x=30-5y in equation (ii) , we get,

2x-y=6

30-5y-y=6

30-6y=6

-6y=6-30

-6y=-24

y=-24/-6

y=4

substituting y= 4 in equation (I)

2x+5y=30

2x+5×4=30

2x=30-20

x=10/2

x=5

hence x=5,y=4