Question

5x-10y=0,x+y=3by unique solution

Answer 1

5x-10y=0
= -10y =5x
=y=5x÷10

Answer 2

5x-10y = 0

5(x-2y) = 0

x-2y = 0

x = 2y                             -(1)

x+y = 3                           -(2)

Putting (1) in (2)

2y+y = 3

3y = 3

y = 1

x = 2y = 2*1 = 2