1. Is the 1st problem y-x or y+x?
2, 2 not equal to 4 when subtracting
4,10 not equal to 4
6,15 not equal to 4
2. x, y. y-x=0
2, 5 x=2/5y 2=(2/5×5/1) 2=2
2-2=0
looking at the 3rd equation
the value of
x=2/5y. 5/2x=y or 2.5x=y
you need to divide the 2/5 to both sides. 2/5 becomes 5/2 or 2.5x.