23. not equivalent because the first row 3x-9y=5 then if you multiplied this equation by 2 it will be 2(3x-9y) = 2(5) so 6x-18y= 10 not 6x-9y=10
24.equivalent because the second row 2y-6x=8 multiplied by 2 is 2(2y-6x)= 2(8) so 4y-12x=16
25. equivalent because the first row 5x+3y=19 multiplied by 2 is 2(5x+3y) = 2(19) SO 10X+6Y=38 and the second row 2x+4y=20 multiplied by 5 is 5(2x+4y)= 5(20) so 10x+20y=100
