Is khan academy enough?

Hey guys, I just wanted to ask you something. I got a 1,370 on my first SAT’s (October 7th, 2017). I live in Ethiopia with english as my second language and so there was a 110 point difference between my English and Math scores, with a 630 on the english section and a 740 Math. I also got a 6-4-6 on the SAT essay. I am going to take it again and am planning on raising my points by 180 points or so (1550+ dream score). Do you guys think Khan Academy is enough to do that, provided I finish ALL the questions and review all the ones i got incorrect? I really need your help guys.