I can just pick random values for x and then figure out what y is. but i'll pick relatively straightforward values and so that the maths doesn't get too complicated. so for example, if x is -2 then y is going to be 2 x -2 - 1 2 x -2 - 1 which is -4 - 1 which is -5 if x is -1 then y is going to be 2 x -1 - 1 which is equal to this is -2 - 1 which is -3 if x = 0 then y is going to be 2 x 0 - 1 2 x 0 is 0 - 1 is just -1 i'll do a couple more. if x is 1 and i could've picked any values here