Question

Solve using substitution method:

4x + 6x = 3xy;

8x + 9y = 5xy

Answer 1

4x + 6x = 3xy---(1)

8x + 9y = 5xy---(2)

⇒ 8x + 12y = 6xy-- (3) (By Multiplying equation (1) by (2))

     8x + 9y = 5xy (Substract equation (2) from (3))

-         -        -

3y = xy

⇒ x = 3

\(\therefore\) From (1), We obtain

12 + 6y = 12

⇒ 9y - 6y = 12

⇒ 3y - 12

⇒ y = 12/3 = 4

Hence, solution is x = 3 and y = 4