simple problem my friend!
First we must replace X with -2,-1,0,1,2
then we plug in -2 in X. 8*-2 is -16 and adding 12 gives us a co ordinate of (-2,-4) now this is not enough so now we must do -1. 8*-1 is -8, + 12 gives us 4. so now our second co ordinate is (-1,4). i will do 1 more co ordinate and then you should be able to finish the problem by yourself :) we now plug in 0 to replace X. 8*0 is 0, easy and 0+12 is 12. so the third co ordinate is (0,12) when you have put all the dots on the graph be sure to draw a line through them and by the way, this is not a biology question lol, good luck!
