ok, id probably b better explaining this in person with a pen an paper than on here but here goes ...if u look at ur table, the rows (x, f'(x) an slope) will always b the same in every table like that ...now, 2 use the table u need a stationary point, sumtimes u have 2 work it out for urself but thats a different matter, but if u look at the question, it tells u that the stationary points r (1,5) and (2,4), so using (2,4) in this example, u no ur x row an can fill it in with 2-, 2, an 2+ (the - and + will always b like that, only the number changes) ...now, in the question it doesnt give u an f(x) equation which ull need 2 differentiate 2 get ur f'(x), but for explanation sakes, lets take f(x) = 3x^2 - 12x, wen u differentiate this, u get f'(x) = 6x - 12 ...now this is wen u use ur x row, its always easier 2 start with the middle number which here is 2, so all u have 2 do is substitute the number 2 where ever u see an x, so it becums f'(x) = 6(2) - 12 = 12 - 12 = 0 which is wat ur table gives u ...now it can get a bit harder with the other 2 numbers, take then 2-, this means that u have 2 choose a number smaller than 2 but never really go for 0 so ur best option wud b 2 use 1, so it becums f'(x) = 6(1) - 12 = 6 - 12 = -6 which is wat ur tables gives u ...do the same for the 2+ by using 3 so u get f'(x) = 6(3) - 12 = 18 -12 = +6 which is wat ur table also gives u ...thats all u have 2 do really, get a stationary point, differentinate ur equation, sub ur x point in 2 the f'(x) an record ur answers ...sorry 2 go on lol, hope it helps tho