x-2y=.9 and 4x-3y=13.1

Question

solving linear systems algebraically using substitution method.

Answer 1

Substitution method :

Given  equations are

x - 2y  = 0.9    ---> (1)

4x - 3y = 13.1  ---> (2)

Solve for x from (2)

4x = 13.1 + 3y

x = (13.1 + 3y)/4  ---> (3)

From (3) substitute the y value in equation (1).

(13.1 + 3y)/4 - 2y  = 0.9

13.1 + 3y- 8y = 3.6

Group like terms.

13.1 - 5y = 3.6

5y = 13.1 - 3.6

y = 9.5/5 = 1.9

⇒ y = 1.9.

Substitute the y  value in equation (3).

x= (13.1 + 3(1.9))/4 = 4.7

⇒ x = 4.7.

The solution of the system is x  = 4.7 and y  = 1.9.